Game Breaking Bug



""This huge oversight renders the rest of the game moot and reduces an otherwise enjoyable game to a pointless exercise, making it one of the most shameful QA blunders in all of video gaming.""

- William Cassidy of GameSpy on the Atari 7800 port of Impossible Mission

The dark side of Good Bad Bugs and a Griefer's favorite variety, Game Breaking Bugs are severe bugs that cripple your ability to play the game involved. They’re almost as old as gaming itself.

Game Breaking Bugs were more prevalent in the earlier days of gaming. Many games that were made after The Nineties seem so much easier because of the reduction in such bugs on average. It was also The Problem with Licensed Games incarnate, since several licensed games actually may not have been as bad as many people say they were...if not for game breaking bugs that slipped past the beta testings (if there was one) and made them literally unplayable or Nintendo Hard.

In these days of mainstream, multi-million dollar titles, developers seem to favor release dates over thorough quality assurance. With the advent of integrated network play, developers also seem to favor releasing patch after patch (if they even bother) and treat their paying customers as unpaid testers. The flaw with this approach is that it alienates a sizable chunk of gamers (in this case, gamers who live in a house without a high-speed internet connection). That, and it's technically illegal in most jurisdictions, anyway.

The growing prevalence of Wreaking Havok (especially in the context of facilitating emergent gameplay) can often cause essential game entities to be launched or pushed into places outside the player's reach or destroyed through unexpected methods. The sheer number of possible outcomes makes this type of game breaking impossible to fully prevent and even the few games lauded for their stability have an occasional hiccup for which the developers can only suggest reloading a saved game.

Note that the presence of one of these doesn't necessarily make the game itself bad; many programs have been quite entertaining despite horrible bugs. One should also probably keep in mind that a lot of bugs only occur in certain builds of the game. In today's market, where even console games can be patched, it's incredibly rare to have a game-killing glitch maintain itself for very long.

The very worst of these can cause a game to be Unwinnable By Mistake no matter what the player does (except, possibly through a counteracting Good Bad Bug). Bugs that always happen at the same point of an Endless Game are known as Kill Screens. Not necessarily the same as a Game Breaker that results from a programming bug; those are typically Good Bad Bugs, which are harmless, but examples of ones that use Game-Breaking Bugs exist; read on..

Action Adventure

 * The Matrix for Xbox (the original one), sometimes would BSOD the console right before a boss (in the mansion), and sometimes you could reset the game, even from playing again from start, and still get that BSOD every single time. Also, the game would sometimes freeze after the helicopter scene, triggered by an unknown glitch earlier in the game that would affect all subsequent saves.
 * The Legend of Zelda Twilight Princess was impossible to finish if the player saved and quit at the wrong time after crossing a bridge which subsequently gets broken. A required character would also turn invisible if the player saved and quit in the wrong area. He could still be utilized, so the game was not unbeatable, but this was still a frustrating bug.
 * In the original copies of the Wii version of the game, the aforementioned required character was outside the room behind a sealed door, in which case it actually was unwinnable.
 * In The Legend of Zelda Links Awakening, you can buy a shovel, then trade it for a boomerang. However, at that point, you can buy a second shovel, leaving you with both. Since the game's inventory is limited to exactly how many items you're actually supposed to pick up, carrying both shovel and 'rang leaves you unable to pick up the last item in the game, which of course is required to win. Oops. So you try to solve the problem by wasting all of your Magic Powder to free up that one extra space in your inventory. Now you can grab that final item! In turn, however, this does render the Final Nightmare's first form literally impossible to beat. Double oops. (The Legend of Zelda Oracle Games, which play very similarly to Link's Awakening, including having an item system that works about the same way, avert this by seemingly having been made with the staff aware of this bug; this pair of games actually has enough spaces that several will never be filled, even when no items are equipped and everything is filling a slot.)
 * In the Eagle's Tower, if you must save and quit before smashing the four pillars, then for Nayru's sake throw the orb used to smash the pillars down a pit. If you don't, it will be erased and the dungeon won't be winnable.
 * The Legend of Zelda Ocarina of Time features the famous "bottle trick," which lets you turn any item in your inventory into a bottle. If used on a useless item, such as the Goron Check Claim after you've claimed the Biggoron Sword or the Magic Beans after you've planted them all, you get an extra bottle you can use to store useful items. But it's possible to turn any item into a bottle -- and if you do this to a game-crucial item? Good luck completing the game! This one treads the line between Game Breaking Bugs and Good Bad Bugs. You can also do the same in Majora's Mask, if you press Start at the exact right time when selling a bottled item to the curiosity shop, then change which item is in the C button slot. You can replace anything with an empty bottle that way.
 * Also in Ocarina, you can freeze the game in the Gerudo's Fortress if you push the Ocarina button right when they spot you.
 * Majora’s Mask has a few other examples as well:
 * There's a glitch where you can equip the Fierce Deity mask outside boss battles. If you try to talk to anyone, or do certain other things, it crashes the game.
 * You can also dive to the underwater chest in Termina Field in normal form, and the "Open" icon will appear. If you push the button, though, the game freezes.
 * The Legend of Zelda Skyward Sword features a game breaker of its own--after completing the Thunder Dragon's portion of the song during the Song of the Hero quest, if you go and talk to Golo the Goron and have not started the other two quests yet, the event triggers will not happen and the game orginally could not be completed until in early 2012 when Nintendo released a patching program on the Wii that downloads the patch and fixes save files.
 * The same game removed the Bottomless Pit fall damage, so that you would be teleported to the last normal solid ground you were standing on 'completely harmelss'. The catch is that because of rushed collision detection in some areas, you can glitch through the scenery and fall through to a bottomless pit. However...you respawn 'on the "bottom" of the bottomless pit', which is mistaken by the game to be solid ground, triggering an infinite loop of falling, respawning, falling...Reset Button!
 * Among notable spots where this glitch is bound to happen, there is a certain miniboss bridge in the Sky Keep. You wouldn't want also to swim too near next to that tree roots in the Ancient Cistern, or clipping through walls whith the clawshots in the wrong place.
 * Bubble Bobble Revolution for the Nintendo DS had to be recalled and replaced because the boss didn't appear on level 30, meaning it was impossible to reach levels 31-100.
 * As did Puyo Puyo 15th Anniversary -- the game stopped saving after 255 auto-saves. This got fixed in a re-release of the game, however.
 * Psychonauts had a quirk where you became unable to use your double jump in a level where you have to jump between flaming grates while the water level is rapidly rising. Fun times.
 * A real breaker is a rare glitch where your Cobweb Duster will disappear from your inventory. Normally an optional device for just collecting mental cobwebs, the route into the final level happens to have three cobwebs impeding your progress, and requires the Duster to take them out. If your Duster disappears, then you could just go back to the shop, collect ludicrous amounts of money, and buy a new one...if you weren't at the Point of No Return (as the game literally calls it) and incapable of returning to camp in order to do so. At least the game autosaves just before you hit the Point of No Return. Of course, you still have to fight against the same boss again.
 * Infamously, in Sphinx and the Cursed Mummy, if you use the second save point during your second visit to Castle Uruk, and then load the game, you will be unable to complete the game, because the door you unlocked will somehow become locked again, with no way to unlock it. Nasty.
 * If you skip the cutscene after the first fight with Death in Castlevania: Portrait of Ruin, a glitch triggers where the fight never officially ends. As a result, once you leave the clock room, the door never opens again. If you head to the right to save, the door won't open again as stated above and thus the game is Unwinnable. Head left and you can keep going...but thanks to a flag not tripping, Vincent won't sell the Rampage subweapon, and Hundred-Percent Completion becomes impossible. Thankfully the bug's been fixed in the PAL version of the game.
 * And speaking about Castlevania, in Castlevania Dawn of Sorrow, when executing a special attack with some shortswords and knives, Soma briefly disappears and reappears behind an enemy...or even a locked door, as long as there is some space behind it. And since most of such doors have the pressure switch to open them right behind them, this can be used for major Sequence Breaking. But go somewhere you're not supposed to go yet (i.e. down a slope you're supposed to double-jump when you haven't acquired it yet) and save just before you realize it...whoops!
 * Metroid Fusion has relatively few glitches, but one of them is severe: when you're finally able to fight the SA-X, its second form (which is usually a sitting duck) will occasionally be invincible. Since the first form is very hard to get past, this is a really unfair glitch.
 * It's also possible at one point to get yourself stuck by sequence breaking too hard. Fortunately, you really have to go out of your way to do this.
 * In Metroid Prime 2: Echoes, you can render the game Unwinnable by triggering the floaty-jump glitch during the fight with Chykka, then using your glitched super-jump to leave the room. When you return, Chykka is gone, and he's taken the Dark Visor with him.
 * Similarly, the first North American version of Metroid Prime got careless with one of its Chozo Artifacts: you get the Artifact of Warrior by beating the Phazon Elite, but the door doesn't lock to make sure you do so. If you leave, save, and come back, the Elite and Artifact are gone for good, and you need all twelve Artifacts to win.
 * There is a bug in Metroid: Other M as stated here, where a door becomes locked and unopenable after you get the ice beam. Nintendo is accepting mail-ins for save files.
 * Tomb Raider: Legend had one of these in the England stage of the game. Activating the levers in the boss room of the stage, whilst passing through earlier on, will render the later boss fight Unwinnable. The only choice at this point is to either hope you have a secondary save (unlikely), use a save game pack if playing the PC version, or start the game from scratch. This last choice is particularly annoying, since England is one of the last stages in the game.
 * Many players have encountered Game Breaking Bugs in Tomb Raider: Underworld at various points that prevent players from finishing the game, although a patch or two has cleaned them up a bit...Except for PlayStation 3 players, who don't get one.
 * ‘’Tomb Raider III’’ has a potentially fatal bug in Lud's Gate; if you save too soon after throwing a switch in the water area with Secrets 5 and 6, a door may be blocked by an Invisible Wall, making the level Unwinnable or preventing you from obtaining the last secret.
 * Soul Reaver 2 has a glitch in the Sarafan Stronghold, after Moebius closes the gates to the tomb of William the Just. If you walk too close at one point in the gate, you pass through. You cannot leave, except by resetting.
 * The developers of Star Control 2 had considered the possibility of someone completely ignoring the Earth Starbase and trying to complete the game without ever visiting there. Their response was to jack up the number of Slylandro Probes until you visited the starbase, which allows certain key variables to be set. Over 10 years after the game was released, someone almost managed to do such a run...until a certain event caused the game to freeze/hang/otherwise become unwinnable because another event (visiting Earth's starbase) didn't happen. It's fixed in the source port, fortunately.
 * The retail version of Overlord had a bug in the brewery area where, if you exited the area by any means (including save & quit) before repairing and using a wheel that activates the elevator to the lower floor, the parts needed to repair it would disappear and the game would become Unwinnable. It was later fixed in a patch that fortunately also made the parts reappear in already ruined saves.
 * There was also a nasty oversight in the first print run that made the uninstaller wipe out parts of the directory it wasn't supposed to. The patch to fix this is prominently included in later editions.
 * In Divine Divinity when one of the bosses died the staff they're supposed to drop could get stuck in a wall. As this staff is needed to complete the game the game becomes Unwinnable. The only way to resolve this is load and earlier save and ensure the boss wasn't near a wall when they died.
 * The N64 version of Indiana Jones and The Infernal Machine had several, documented here (starting around 1/3 down the page). Bugs include random freezing possibly associated with a music loading error, getting stuck inside of objects and walls, getting stuck between objects, objects not functioning as they should due to unintentional Sequence Breaking, and a glitch that caused the player to enter the same room over and over again until they killed themselves to fix it.
 * The PC version of LEGO Harry Potter: Years 1-4 has a glitch where you can get the Lord Voldemort character token before getting all 200 Gold Bricks, but made it impossible to return to Hogwarts. And this is far from the only one, nor is it the worst. It's pretty sad when a modern game has a Game FAQ devoted to listing all known glitches and how to avoid them. Several of these glitches have the ability to render your save file unplayable, or prevent 100% completion if you're unlucky enough to encounter them. It's pretty clear the game had only a cursory QA check done before going to print.
 * A particular example of a bug which renders the game impossible to win if you make the mistake of saving at the wrong time -- Beneath one of the classrooms is a section you need to visit to collect unlockables. At the end of the section, a Lego dragon will grab you and toss you back up into the classroom to exit -- Normally he will, anyway. Sometimes, he misses. At this point, he will not toss you again and you are permanently stuck. If you reset the game, you'll lose everything since your last save; if however you save and reset after this occurs, you might think the dragon will reset and toss you again, but no. At this point your save file is garbage and you will have to delete and start the entire game over if you want to continue.
 * Assassin's Creed: Brotherhood is an incredibly buggy game. Falling through the scenery is very possible and the only way out is to restart the game.
 * On release, the game had bug with the tunnels. Ezio would be stuck in an endless loop when going through the tunnels. There was nothing that could be done save for starting the game from the beginning. Made even worse by the fact that you must use a tunnel in the game once. Players had to hope the bug didn't occur at that point. This bug however, was patched.
 * The multiplayer has become almost unplayable due to the recent flood of bugs. Players turning invisible or even invincible, Wanted gamemode not choosing a target and Manhunt rounds getting screwed up in one way or another. The servers are also exceptionally laggy, causing a lot of other game breaking problems.
 * Batman: Arkham Asylum had a bug that randomly corrupts your savegame. The worst part is that it can be triggered by completing the story mode on 100%. Hundreds of puzzles, lost.
 * Heavy Metal: F.A.K.K. 2 for PC at one point has you progress by entering a cave, but your entry is blocked by interconnecting stalactites and stalagmites. Fortunately, there is a pile of unstable meteorites right in front of it, so you can lay down a thermal detonator and wait a few seconds for it to explode, clearing the way for you to proceed. Unfortunately, this pile of unstable meteorites will sometimes be located near the ceiling of this cave mouth, and not the floor. Thermal detonators can only be placed on the floor, and other explosive weapons like the rocket launcher have no effect on these meteorites. The only way to proceed is to either start a new save file and hope that the meteorites spawn on the floor this time around, or to use the cheat codes conveniently included in the game's readme file for just such an occasion - simply turn off clipping, fly through the barrier, and turn clipping back on again.

Action Game

 * An entire page could be spent listing the various Game Breaking Bugs in Hidden And Dangerous; fortunately, this got better with patches and an eventual free re-release.
 * Characters in vehicles often grew to twice their normal sizes, causing half their bodies to stick through the roofs. One mission featured a vehicle that had to be driven. It might be larger than the hole that this vehicle must pass through, forcing the player to cheat past the level.
 * If you ran out of ammunition, you fell through the ground.
 * The freeware version/latest patch introduces a new bug; some maps on hard difficulty allow enemies to empty all bullets in their clip in one frame. The result is instant destruction of the boat containing your whole team. Affected missions are still winnable if you can kill all enemies before they can attack.
 * The Game Boy Advance version of The Fellowship of the Ring was plagued with bugs. Most of them were merely agonizing, but there was one place where, in order to progress, you need to save the game during the Fade Out between scenes. If you time it wrong, you lose the save file.
 * X Men Legends II: Too many items in your Hero Stash and it'll freeze upon taking out any Giant Mook. Keep it below 20.
 * Max Payne sometimes had a glitch on the final stage where the cutscene would fail to activate, resulting in Max firing a couple shots at Nicole and the game freezing. Reload.
 * Alternatively, Nicole could snag the wall next to the gate leading to the helicopter and stop. Max would then catch up and unload hundreds of bullets into the back of her head until you reloaded.
 * Final Zone II, at least on some copies, had a problem where a horrible buzzing sound would sometimes start after the intro cutscene and continue throughout the game. This may have been due to a defect in the CD.
 * The Cursed Crusade, at least on the Xbox 360, will corrupt your save if it crashes during a chapter load, preventing it from loading anything beyond the crash point.
 * In the 2008 Alone in The Dark game, there is a sequence where you must drive a car from a building near Central Park all the way through some of the nearby streets in order to escape a gigantic fissure wreaking havoc on the city, however, during the very last part of the ride, a very nasty bug will sometimes prevent the map from correctly loading during the last jump, making you fall to your death and forcing you to repeat the whole driving sequence.

Adventure Game

 * In Faxanadu, the reward for beating dungeons are items which can be used to clear certain blockades or obstacles in certain screens. However, it disappeared after being used, and if you left the screen from the left side (probably to refill on health since the level layouts often sport monsters camping near ladders, from where you couldn't attack) the blockade would reappear, but the items would not respawn anymore even after beating the dungeons again, making the game unwinnable.
 * Gabriel Knight 2: The Beast Within featured a crippling bug at the end of Chapter 4 that would prevent the player from progressing to the next chapter.
 * The original Quest for Glory IV: Shadows of Darkness was originally rushed out, bugs and all. Most of them were fixed in one way or another, but by the time the dust had settled, a few remained:
 * The most infamous was the bane of gamers everywhere, Error 52. Midway through the game, thanks to issues in dealing with faster computers, one crucial area in the swamp became impossible to leave without crashing the game. QFG message boards then-and-forever had a new favorite topic.
 * This is also one of the few Sierra games that has a bug that occurs at the end of the game. When fighting Ad Avis, the hero has a staff that turns into a spear; this spear sometimes turns into the now dead Ad Avis about halfway back to the player character, who then kills our hero with a spell shot from a different area of the screen. This bug appears to occur randomly.
 * Yet another QFG IV bug is the disappearance of the Domovoi after Day 5.
 * While the CD version fixed most of the bugs, it also introduced one particularly glaring one: as a wizard, after the final battle (won by using a certain spell on Ad Avis), using the Summon Staff spell to complete the game would actually render it unwinnable, as the game would not allow you to use the staff properly, and then time would run out, the Dark One would be summoned, and it's game over. The only way to get past this bug (which happens every time) is to cast the certain spell again, then summon the staff. But what most walkthroughs don't tell you is that if you cast the spell at certain specific places, the game will consider those casts as "misses" in the final battle, resummon Ad Avis, and have him kill you instantly. And those specific places cover more than half the screen.
 * Quest for Glory III didn't have quite as many, but a few irritants still showed up.
 * The most memorable: As a Wizard, using your last Dispel Potion in the Lost City froze the game. Every time. The only way to bypass that point was to fight the monster that the Dispel Potion was meant to take care of for you, which for a Wizard was often lethal (it was a tough fight even for a Fighter.) And not being able to use the potion screwed you out of points, which made 100% completion impossible.
 * In the same line as Error 52, there's Error 4 that crash your game during the Simbani initiation.
 * King's Quest IV had a bug that only showed up on slower computers, thanks to the odd way in which the game calculated time for various characters. Rosella and all the other characters moved slowly because the computer wasn't fast enough to draw everything at full speed. The game was still playable, just slow. The one exception was the ogre, which used a more real-time timing method -- he would travel across the screen in a certain number of seconds no matter how slow the computer was. In one plot point, Rosella is in the ogre's house and must reach the door before he caught her, only possible on PCs which ran the game at the intended speed. The only way around this was to take the saved game file to a faster computer and play that scene there.
 * A devious glitch with the Text Parser in Leisure Suit Larry 2: Looking For Love (In Several Wrong Places) snuck into the game just the night before the game shipped: Near the end of the game, the player is expected to combine an airsick bag with a bottle (to make a Molotov cocktail, the bag serving as its wick). The only acceptable input was some variation of "put airsick bag in bottle", because a) the parser was (badly) written specifically to understand fully formed English phrases instead of "adventure game shorthand", b) a completely unrelated bug had just been fixed by another coder by turning the word "bag" into a verb and c) no one cared to fix it in time, because Sierra's testing policy at the time was to use the longest possible phrase in a situation and see if it works. Contrary to popular belief, the input does not require the word "the" several times; the point is that "airsick bag" works, whereas the common shorthand "bag" doesn't (since it's a verb).
 * Graphic adventure Simon the Sorcerer 2 had a strange bug where a certain character and the object you needed to give them were on the same screen, and you could successfully use the SCUMM-style interface to "Give to " despite not being in your inventory. This skipped a large chunk of game and messed up many dependencies.
 * In The Curse of Monkey Island, one of the tasks on Blood Island requires you to
 * In copies of the game that don't have this bug, Guybrush just mistakes your intention and chastises you for suggesting he harm an innocent dog.
 * Escape from Monkey Island has a nasty bug in the PC version of the game. At one point you're in a sushi restaurant, and you have to stick a fork in a track on a table to stop a sushi boat moving. This is intended to cause the chef to come out of the kitchen and if you are quick, you are able to grab something from the kitchen. In the PlayStation 2 version, this is fine. In the PC version, however, you can hear the chef say his dialogue before you've actually done this task, and far worse, when you've done it there is nowhere near enough time to go into the kitchen and get what you need before you get thrown out. The game was originally designed for Windows 98/2000/ME with certain graphics cards, anything more powerful will run the game but likely cause issues.
 * The PlayStation 2 version had a nasty (and seemly random glitch) that causes Guybrush to be permanently rooted to the spot and nothing seems to get him moving again.
 * The original 8-bit text adventure of The Hobbit was terminally bugged in early releases - among many weird glitches, Gollum would ask you riddles, but pay no attention to the answers, making it impossible to get the ring.
 * Grim Fandango had an elevator which the player needs to stop at a certain point. However, if you had a computer with a fast CPU, the elevator would move too fast to be stopped, and the player won't even realize stopping it is possible. This was luckily fixed with a patch.
 * In Putt-Putt Saves the Zoo, there is one point where you have to ride a log raft to the other side of the river. In the 1999 version, when you make it to the other side, if you simply click on the space where Putt-Putt gets off instead of going somewhere else, he starts talking. Skip it, and the raft disappears and it never comes back. You don't have anywhere to go either, so your only choice is to reset the game. This didn't exist on the 1995 version either.
 * The original Colossal Cave Adventure got ported to many, many systems. Somewhere along the way, one version picked up a couple of bugs, and then the bugged version got ported further by people who didn't check that the version they were copying could be completed. Several of them are potential game-breakers, but the simplest example is one of the many treasures you need to collect and store in order to unlock the endgame. The treasure is just lying in a remote chamber, and all you have to do is pick it up. In the bugged versions, typing "get spices" recieves the response "You can't be serious!" No spices means no endgame.

Card Battle Game

 * The initial release of SNK vs. Capcom Card Fighters DS had a fatal bug during its New Game+ mode where one opponent's dialogue wouldn't appear when spoken to and consequentially couldn't battle them. Since you needed to defeat everybody on a floor to move on, that's as far as you could go. After the glitch was discovered, you could send SNK Playmore your bugged copy for a fixed one.
 * Yu-Gi-Oh!: Nightmare Troubadour has a glitch that can cause Pegasus to disappear from the game after a certain point, rendering Hundred-Percent Completion impossible.
 * Magic: The Gathering occasionally releases a card that has to be reworded after printing because they either cause infinite loops or don't work for whatever reason.
 * One particularly goofy example was a red enchantment that would randomly change the target of any ability that was played; it was accidentally worded in such a way that it would try to redirect its own ability, effectively creating an infinite loop the first time any player did anything.
 * There was even one card (Fatespinner) that was fairly mundane by the game's standards, calling on the opponent to pick a handicap each time they got a turn. The problem? When the card was first added to the online version of the game, it didn't provide them with a way to resolve that decision, and they could do nothing but wait for their time to run out and automatically lose. Needless to say, decks built around doing nothing but getting that card into play became wildly popular over the next few days to the point that they had to ban the card online until they could fix it.
 * Floral Spuzzem: The original wording of the card effect was that the Floral Spuzzem itself (not the player) got to decide which card got targeted by its effect. Guess how long you'd have to wait until a piece of cardboard spoke up to give you its opinion on the matter?

Driving Game

 * In the American version of Tokyo Xtreme Racer 3, the game's money system is deflated tenfold--you earn 1/10 as much money as in the Japanese version, and everything costs 10% as much. Unfortunately, the money requirements to encounter two particular opponents were not adjusted; as a result, one of these opponents, Whirlwind Fanfare, requires more money than you are allowed to hold--you can hold up to 99,999,990 credits, she requires 100 million. Since you need to beat the first 599 opponents, including her, to challenge the Final Boss, it's impossible to beat the game without an Action Replay.
 * In Mario Kart DS, the game can be completely frozen simply by holding A and B together and turning on the steps of the Luigi's Mansion track.
 * The arcade game Wangan Midnight Maximum Tune has a card cloning trick that doubles as a Good Bag Bug and this. Doing said trick is highly frowned upon because it literally breaks the game--specifically, the card reader. If you know what the trick is, please don't do it.
 * The whole of Big Rigs Over the Road Racing. This one is unique in that the game is broken in such a way that it’s impossible to lose.
 * The PC version of Wipeout 2097/XL physically runs faster on faster PCs, quite unique for a game made in '96 long after the demise of the turbo button. Within a few years the game was impossible to play. A Game Breaking Patch was released which claims to fix this and add local multiplayer, but also seems to require the game to be installed in c:/Wobble for some reason and is pretty unlikely to work even then.

Fighting Game

 * In Naruto: Rise of a Ninja downloading Shikamaru from Ubisoft on Xbox Live would cause your game to freeze if Naruto was hit by anything like a log or spikes. The Jiraiya/3rd Hokage download corrected this problem.
 * Soul Calibur III had one of these; Game FAQs has a writeup on it. Essentially, it's possible if you do something in a different game (but one whose save file preceded your Soul Calibur III save on the card), you may find your next Chronicles of the Sword run-through wiping out...well, if you're lucky, only your Chronicles progress. In some cases, the whole save file may get wiped. Some have reported that the card itself can die as a result. Unpleasant, to say the least.
 * In the tournament scene, the infamous G-Step glitch, which allows one to immediately block after sidestepping, turned Soul Calibur II from an excellent tournament game to nigh unplayable at high levels due to it being really hard to hit anyone. A less game breaking version exists in every successive game, but it's still responsible for the dominance of turtling strategies.
 * The initial version of Mortal Kombat 4, which wasn't technically supposed to get out to the public (it had missing Fatalities, no Kombo Limiter, missing characters, no endings...) had a bug where one character could lift his opponent to the top of the screen by using a special move properly. The "lift" wouldn't wear off until the target was hit by something else, and nothing could get up that high, so the game was effectively stuck, especially if the game timer was disabled.
 * Revision 3.0 had a bug where performing Reptile's Acid Spit fatality on Scorpion would crash the game.
 * The initial release of the PAL version of WWF No Mercy on the Nintendo 64 would, without any explanation or warning, delete all saved data on the cartridge. The North American version also had this error, stemming from a faulty battery responsible for the saved data.
 * This is true of any game which has a battery save system. The second the battery fails, the save is lost. Some games were able to recharge the battery with regular play, so that as long as a game was played regularly, the player shouldn't notice any lost data. Of course if you lost the data, you had to start the game over. Even worse however, is that if the battery does completely go, and cannot be recharged, the game can never be saved and turned off, meaning that the only way to get to the end would be in one sitting. Playing an old 100+ hour game that ran on an internal clock to do everything, such as Pokémon Gold? Better have a plug for your Game Boy, or sucks to be you.
 * This was quite a common problem with Pokemon Yellow due to cheap parts being used because of the demand.
 * Marvel vs. Capcom 3 has the Zero Glitch. If you used his Doppelganger Attack to snap back the enemy when the enemy has an assist, the enemy will not come back in to replace the one that got kicked out. Which means that you could stall for time over...but if the time limit was set to infinity, the game would really be broken after that.
 * A glitch that ends the round in a similar way exists in the early arcade version of Blaz Blue Calamity Trigger, when grabbed as Rachel, if you break the throw and casts her wind drive downwards at the same time, her opponent remains completely frozen and invincible until the time runs out if a time limit is set. If her opponent is Carl, the Carl player can still move his puppet while being stuck in this state, though.
 * The 1.04 patch for Street Fighter X Tekken added a nasty glitch where if Rolento's projectile knife collides with another projectile, the game will crash. Tournament holders have actually considered banning Rolento until the glitch is fixed.

First Person Shooter
"- fixed: jaguar floats across screen at treetop level; - fixed: size of the moon;"
 * Far Cry 2 has the infamous 27% Glitch, so named because it occurs when you have gotten to 27% completion. It only happens sometimes, but what does happen is that one of the factions' mission-giving NPCs fails to spawn. This prevents you from completing the game, as you have to do all the story missions in the Northern District to go to the Southern District and then finish the game. The only way to avoid it is to restore from a save before 27% completion and hope it doesn't happen again.
 * Its other bug is that at some point, the taped messages you find - which explain the story and set up the motivation of the Jackal, who is the guy you're hunting and your entire reason for being there - stop being new messages. After that point, every tape you find only has the same message on it, which means that the Jackal's character development stops halfway, destroying the storyline. You can still play though, the plot resolution just doesn't make any sense.
 * Crysis had one, and at the most climactic moment of the game too: the final boss would randomly become untargetable (and thus invulnerable). This was made especially pernicious as the battle in question involved three separate phases and the bug could manifest itself during any one of these. Saving the game mid-fight did not help, and the community never quite figured out what caused the dreaded bug. The only solution was to save before the fight and keep reloading until it went right. This could take as many as five or six attempts.
 * The stage "Relic" had one. When you fight the soldiers in the graveyard, sometimes the helicopter you are supposed to leave in never arrives. You have to replay the whole level again to fix it.
 * Crysis had plenty of game ending flag bugs right from the very beginning: If you're playing a second time, you'll probably want to run straight to the action. Nope, sorry. Using your nano-suit abilities, given almost immediately after reaching the beach, if you get to the point where you meet your first teammate too quickly, he'll just stand up on the cliffs. Nothing you can do except starting over will get him to come down.
 * Crysis and Crysis Warhead both had bugs where triggering the start of the final boss fight would remove part of the map's clipping data. If the player happened to be standing in this part of the map, they would fall through the level and be forced to reload. If the player didn't have an earlier save or couldn't get to a safe part of the map fast enough, they had to restart the level.
 * In TNT: Evilution (one half of Final Doom), the first secret level, "Pharaoh", is impossible to finish in single-player without cheating or engaging in Sequence Breaking because the level's designer mistakenly flagged a vital key as multiplayer-only. The creators, TeamTNT, soon released a patch to correct the bug and make it winnable. To this day, however, id Software has never fixed the bug in their distribution. However, it's not actually impossible to complete, thanks to an oversight by the map author (and a couple of bugs in the Doom engine). By strafe-running onto the right-hand throne, you can in fact activate the switch hidden on the "backrest" to open the door to the last few areas, and skip almost the entire map. Even with this method, you can still achieve 100% kills, items and secrets, as the key isn't completely necessary to complete the map.
 * Similar tricks allow you to get into the secret stage of Doom 1's 3rd episode without rocket-jumping. iD software actively tried to prevent one of those tricks from being usable (pressing the switch from outside the room - not unlike the trick for the backrest switch in Pharaoh). The strafe-running trick was found too late for iD to do anything about it, though.
 * The Mac version of Doom II had a bug in one of its MIDI files that caused the game to crash on Level 29. Fortunately, this was quickly patched.
 * Call of Duty: Black Ops has a strange one - in a level towards the end of the campaign mode, using a shotgun to get your way through the level, without warning an error message will appear warning of "more than 160 bones" (or, sometimes, "bodies"). The exact cause of the error is unknown, and after closing the message box, the game will essentially reset itself and return to the main menu. Reloading campaign will send you back to the start of the level, so goodbye to all the hard work put in before the message.
 * Apparently this glitch can also appear on other COD games made by Treyarch. Hmm.
 * On the penultimate mission where you discover you were brainwashed, you get punched while running down a corridor, however this sequence would often break and after being punched, Mason would be stuck in place and Hudson would appear in his Vietnam gear complete with sunglasses, the unfunny part is you would be stuck and the level has no checkpoints as there's no combat in it so you have to start the entire mission again.
 * Modern Warfare 3 has the infamous "Reliable command buffer overflow" bug.
 * Boiling Point: Road to Hell was essentially a game strung together with fatal bugs, as well as a whole bunch of ones not completely fatal, but amusing nevertheless. Excerpts from the patch notes that fixed these problems are now somewhat of an Internet legend:

- fixed: npc die on contact with grenades, and not from the actual explosion;


 * F.E.A.R. had a little bit of an oversight that would render the game unbeatable. At one point, you're asked to download data from a laptop. However, there were laptops with downloadable data all around to get the backstory, and you're told to download this data way after you see this laptop. But once you download data from a machine, you can't do it again, even with that mission critical laptop. The mission objectives also didn't say that it was completed. You basically have to restart from the last save and wait for the objective to be given, then download the data.
 * One of the game's later patches fixed this, so that Betters will tell the player, "I see you've already checked the laptop."
 * In Left 4 Dead, there exists a hiding spot on the Survival-only map, Last Stand. Behind the lighthouse there is a pair of large rocks at the edge of the cliff and a small patch of ground between them. It's possible to jump over these rocks and land behind them without falling off the edge of the map and dying. Hidden behind these rocks, you're completely safe from the Infected unless you get roped by a very well-placed Smoker. Considering the aim of Survival is to survive for as long as possible, this pretty much makes Survival on that particular map unloseable for someone who can make the jump and knows where a Smoker has to stand to be able to attack them.
 * In fact, just about every Survival map in both Left 4 Dead and Left 4 Dead 2 contain spots like these where almost nothing can reach you. In some spots, literally nothing can reach you allowing for utterly absurd times (people have managed to survive for DAYS using some of these spots). The developers attempted to stop this from happening in Left 4 Dead 2 by spawning spitter acid in areas that the game considers out of bounds but the addition of the Grenade Launcher meant that you could launch people up to spots where the spitter acid can't spawn. And the thing is Valve can't patch this glitch; it would require completely retooling the physics engine, something that can't be done with a simple patch.
 * In Left 4 Dead 2, throwing boomer bile into the safehouse at the start of a level, then having all but one person leave the saferoom, will cause all the zombies to go for the bile as usual. After the bile has run out, though, the zombies will try to kill the person inside, which they can't. With the massive group of zombies around the saferoom door, the game is unable to spawn anymore, allowing the remaining survivors to run through the rest of the level without any opposition, providing the person in the saferoom does not go idle. Special infected will still spawn, but otherwise, this makes every non-finale level pathetically easy.
 * Killing Floor has a glitch that can be triggered by swapping from first to third person camera in observer mode right when the round ends. If you're unfortunate enough to trigger it, you'll spawn with a third person camera. Since the game relies heavily on ironsights, good luck hitting anything. Oh, and you'll get a nice inventory glitch to go along with this glitched camera that erases items from your inventory after you switch. And whether or not you can pick anything up seems to be determined by chance. Getting back into observer mode (by dying) is the only way to fix it.
 * Medal of Honor Allied Assault had a rather nasty bug in the Destroyed Village map. With some careful jumping, a sly player could actually scale the Invisible Wall and go under the map in a feat called Landsharking. The landsharker is completely invulnerable to damage, but can still shoot other players. Plus, since they're under the map, it's impossible to hide from them unless you're on a second story. This would essentially make the team with the landsharker unstoppable. The problem was eventually fixed.
 * The original release of Quake total conversion Malice had a really bad example of this. In level 8 there is a deep shaft which the player has to parachute down in order to complete the level. But unfortunately the developers forgot to put the parachute in the level! This made it completely impossible to complete the level unless you used the 'fly' cheat from the console. A patch was hastily released by the rather embarrassed developers.
 * In Team Fortress 2 (at least the Xbox version), it’s possible to sometimes walk around in the sky above the second cap of the first part of the Dustbowl map. If an Engineer manages to build a sentry up there, then the sentry is effectively indestructible, and getting past it without going into range is almost impossible.
 * While rare, it was possible in the first Halo to checkpoint right at a point of inevitable death. (Hello, sticky-grenade). This would trap your character in a Cycle of Hurting and force you to go back to the start of the level. Future games had a failsafe feature that reverted the game to an earlier checkpoint after a certain number of deaths in such a situation.
 * Half-Life: Opposing Force has a door about 2/3 of the way through the game which, if opened, may crash the game. Unfortunately, opening this door is also the ONLY way to progress. There are a number of tutorials online on how to engage noclip and skip straight to the next working point in the game - it seems that whatever is behind the door is what crashes the game, not the act of opening it, because even looking in that direction while noclipping triggers the crash, hence the need for tutorials instructing how to noclip to the next area.
 * There's also a bug where you get stuck inside an elevator platform, making it impossible to move, the only way out being either a noclip cheat, or reloading the game and hopping like a complete idiot while riding the elevator in hopes that this will prevent the bug.
 * Half-Life 2 included a well-known bug near the end of the game (during the chapter "Our Benefactors") that made it impossible to proceed past a certain hallway. but moving around, jumping, or crouching while the field is in effect will make it impossible to jump at all, even after the field has turned off. This usually goes unnoticed until a few rooms later, when a seemingly innocuous waist-high fence becomes an impassable barrier. The only way to 'fix' the bug is to reload from an earlier save point or start the level over entirely.
 * The May 2010 mega-update (which ported the whole game and Episode One over to their newer game engine) introduced, among many other bugs that have yet to be fixed, one that causes the scripted sequence to not run, trapping you in the back room with an inert Alyx. They did patch this a week or so in, but apparently every copy of the game was susceptible.
 * Another issue that Valve apparently hadn't planned for (and that mods sometimes activate without knowing it) is that the nasty but slow poison headcrab zombie shouldn't appear in a level where there are also barnacles around. Most NPCs that blunder into barnacles get pulled up and eaten by the monster, but the game crashes if a poison zombie is grabbed, as they hadn't programmed in any sort of code to handle a poison zombie being attacked by a barnacle.
 * At one point in Shogo: Mobile Armor Division, you're supposed to take an elevator down along with your partner. Unfortunately, 90% of the time your partner would inexplicably explode into bloody chunks while riding the elevator with you (presumably the game somehow thought she was crushed by the very elevator she was inside.) Oh, and this was an Escort Mission, so it's game over if it happens to you.
 * Daikatana has a host of these, including a glitch in the Lair of Medusa level where, when played in co-op, the player can get stuck to the floor when spawning, and get stuck in an infinite loop of respawns and telefrags by the other players. The only way to get out of it is to noclip past that spot.
 * The second level of the first episode has a large door that is opened by a ghost in the cutscene that starts the level. Cutscenes are removed from co-op mode, resulting in the first episode being unbeatable in co-op without cheating.
 * House Of The Dead: Overkill hits the player with one during the Crawler boss fight. The only way to avoid taking damage from Crawler's swipes is to shoot its claw as it prepares to attack. However, on occasion, Crawler won't take damage even if you shoot the marked weak spot. The result: you're forced to take several hits until Crawler switches locations.
 * The game's "Extra Mutants" mode (which adds enemies to a level) appears to be an afterthought, as enemies spawn in inconvenient (for the game) locations. In one scene in "Ballistic Trauma" where hospital doors blow open and zombies swarm out, one female zombie only present on Extra Mutants can get stuck behind one of the doors. You can't kill her, and the scene won't advance until all enemies are dead. Unwinnable By Mistake ensues.
 * Not quite game-breaking, but there seems to be a rare bug where mutants forget you're in cutscene mode (i.e. unable to shoot any of them) and start attacking you anyway.
 * The 1.0 versions of both Descent and Descent 2 infamously had a fatal bug that caused their final bosses to be unbeatable on any difficulty higher than Rookie.
 * In Call of Cthulhu: Dark Corners of the Earth there is one infamous sequence in which you must fire at several enemies using a deck-mounted cannon. The problem is while the enemies are still there, you can't see them. Nobody knows what causes this bug, and the only known solution is to use the savegame of somebody fortunate enough to not encounter it.
 * In another part of the game, there is a cart you are supposed to get onto. On some games, the game just plain refuses to let you advance. In a rage, people realized that shooting a specific point on the cart will let you on.
 * GoldenEye has one with the Invisible Bond cheat. When activated, enemies can't see you, but neither can NPCs. Because of this, they can't give Bond crucial items or other things to complete objectives, making the level unwinnable. However, since it is a cheat you can turn on and off at will, it doesn't pose much of a problem, and most players would be using cheats to screw around anyway.
 * The first release of Sin had a rather nasty bug during the Chambers of Darwin trials. After the second chamber, a guard is supposed to open a tunnel passage for the third one. Actually, the soldier keeps redirecting you to the tube, without opening it: more frustration comes through the fact that you're slowly dying during the tests. A couple of months later, Ritual released a patch to cure this glitch.
 * Marathon Eternal is a fan-made game using the open source version the engine. On the level "Roots and Radicals", there's a medium-sized room which spawns endless amounts of Enemy and Weapons sprites, not to mention unlimited Helpful Drones. Now, there is a wall next to the spawning pad which can not only be switched on to block off the troopers but smash them during their short run outside that area. Let them spawn instead of blocking off the path can make the game Unwinnable because Alephone will block off Hit Detection due to memory usage exceeding limits.
 * On that note, the original Marathon had what is possibly the biggest bug of all time. If you installed it on your computer, IT DELETED EVERY SINGLE FILE YOU EVER HAD. Luckily, this was found before release, but they already had quite a few boxes of the games shipped. The shipments had to be recalled.
 * In the original Quake, sometimes you will lose the runes from previous episodes if you die and reload. Keep multiple saves.
 * The Activision PC game Revolution had a level that actually could not be beaten without a cheat code. A patch supposedly fixed it, but it would not work on existing saves (requiring that the game be completely started over). Here's a very amusing review at GameSpot.
 * Medal of Honor 2010 has a lot of these bugs, such as scripted events failing to activate, and parts of levels failing to draw in, causing you to fall to your death in the void.
 * In the original Deus Ex, it was possible for the player to bring the game to a grinding halt by succeeding when the game needs them to fail. At one point, the plot requires the player character to be arrested and detained at UNATCO headquarters. The main character emerges from a subway station and is confronted by a squad of UNATCO troopers, a pair of cybernetically-augmented agents and a heavy-duty bipedal combat robot. Normally, the player character can choose either to go quietly or get the tar whipped out of him and wake up in a UNATCO prison cell. However, a well-placed electromagnetic pulse grenade will cause the combat robot to go haywire and turn on the UNATCO troops who will forget about their real target as they try to defend themselves from the crazed robot. It is entirely possible for the robot to wipe out the enemy, with or without the player character's assistance and be easily finished off by the player. Unfortunately, with no way to advance to the next chapter, the player becomes stuck in the decrepit shanty town that surrounds the subway station.
 * In Sniper Path Of Vengeance, towards the end of the game there is a level where you must board an elevator to get to the next level. The game auto-saves after each level, and on the first attempt at conquering the next level, there are no problems - but if you reload from the auto-save, the elevator doors will never open again, and you get stuck in the elevator. Thankfully, the autosave feature creates a new save for each level, so you only need to replay one level if you forgot to save right after exiting the elevator.
 * The PC port of Turok 2 seems to have a major memory leak, causing it to slow down to slideshow levels (even on fast computers) after playing a few minutes, and possibly crash.

Massively Multiplayer Online RPG
Let's not forget that the buff was self-stacking, to boot -- instead of just doing double damage once, they did max-buffed damage until you became a greasy splatter. With everything else with Ninjutsu (longer aggro range, Invisibility, decent defense, especially to Area-effect attacks..), they were pretty much The Way To Kill A Player. There was a screenshot floating around during this time showing an Energy Melee/Ninjitsu boss who had hit the playtester for over 9,000 points of damage. Even the toughest archetype in the game, the Tanker, caps at around 3000 HP. This bug has been fixed as of June 2009. but it's notable for being one of the hardest-hitting bugs in the game's several-year history.
 * The initial release of the EVE Online: Trinity update contained a glitch that prevented some Windows XP systems from booting until fixed by a rescue disk.
 * How this actually happened is definitely a “what not to do” in programming. The EVE program folder contained a file called boot.ini which contained various parameters...boot.ini is also a critically important Windows system file located in the root of C:\. During the patching process, the patcher was supposed to delete boot.ini (in the EVE folder) to allow a new one to be written, but a typo meant the patcher looked in the root of the drive. If you had EVE installed on the same drive as Windows, you got an unbootable system. Since that incident, the file in question is named start.ini.
 * A similar bug existed in pre-release versions of Myth II. Uninstalling the game wouldn't wipe just the game's files, it would wipe one level up in the file tree. This could result in the wiping your entire hard drive.
 * Each new release of EVE tends to include at least one bug that breaks gameplay as well. Most recently with the Crucible release, they broke the NPC police mechanics that protect players in the space controlled by some of the NPC factions.
 * In April 2009, City of Heroes had an incredibly nasty bug in its new Mission Architect feature: the Ninjitsu powerset that players can use to create custom enemy groups has a major damage buff given when the user attacks while stealthed. It's supposed to work only for that one attack and then the stealth wears off, as usual with the Stalker archetype. It didn't quite work as intended: custom enemies got that enormous damage buff for all their powers, whether or not they're stealthed. It meant even Tankers and Brutes could very, very easily be killed very quickly by any enemy, even standard minions, that had the powerset.
 * Ace Online had an event in 2009 called Bloody Valentines. In this, nation-aligned Elusive Scout Guards would spawn in maps defined as the main territories of ANI and BCU, and they had a chance to cough up Broken Hearts. So far, so good. The mechanism they used for this spawning was that as mobs were killed in a specific map (for example, ANI's Relic map), sometimes a normal monster's death would cause an Elusive Scout to spawn (for this example, an ANI-aligned Scout would spawn). However, the GMs messed up in that they also made the monsters in Safe Maps (Relic Safe in this example cannot be invaded by BCU) capable of spawning Elusive Scouts which could not be attacked by pilots aligned to them. This eventually caused maps like Relic 1, Doleful Plains 1, and even the Desert of Ardor to be filled [[media:motivator252941.jpg|to the population limit with Elusive Scouts]], preventing newbie pilots from safely grinding training in the Safe Maps. The GMs eventually limited their spawning to the new Episode 3 Maps and New Bark City to prevent the Safe Zones from being clogged up again. Most interestingly, ANI (of the Subagames Artemis server) made great use of the Elusive Scouts during the Horos Mothership Defensive of April the 19th. As the countdown to the Mothership's appearance loomed, several pilots went on a great Elusive Scout spawning spree, culling vast numbers of neutral monsters in their territories to create Elusive Scouts (which did not despawn for the Mothership Defensive!). During the great war that followed, the BCU army was beset not only by the usual formations and gatecamps of the ANI regulars and elites, they also had to contend with a swarm of Elusive Scouts jamming up their targeting reticules and pumping missiles at them - quite a significant number of BCU regulars blamed their deaths on Elusive Scout-launched missiles. What a cunning ploy by the Arlington Boys, to utilise the Event Mobs in such a fashion!
 * Kingdom of Loathing had the meat vortex bug, caused by an improperly coded check to ensure the meat (currency) wouldn't underflow. The meat vortex bug allowed players to gain 18.4 quintillion meat instantaneously, which wrecked the in-game economy. Fortunately, Jick proved that he doesn't fail economics forever by cleverly fixing the problem via "meatsinks" - the Penguin Mafia (who would show up at a specific adventure site and randomly steal large portions of an adventurer's meat), the Council's attempts to stop the Penguin Mafia (which required a massive amount of donated meat), and, after a few more sequences along the same lines, the foundation of Uncle P's Antiques (overpriced, unsellable knick-knacks designed to get the last traces of "bugmeat" out of the economy). A later meat generation bug was discovered, but it was fixed quickly enough that the exploiters just had their accounts disabled.
 * Meridian 59: Word of God says that one of the early expansions had a new zone that required a special spell to access. However, the components to cast the new spell were exclusive to the new area, producing a kind of key-locked-in-chest scenario. The developers caught it and swiftly threw in a Giant Space Flea From Nowhere guarding enough of the components to cast the spell.
 * World of Warcraft experienced a nearly-game breaking bug in its early days. A boss in Zul'Gurub released a bad disease (called Corrupted Blood) that could spread, but only to players nearby. The disease was not meant to get out of the instance the boss was in, but a clever player could release a pet, give the pet the disease, put the pet away, travel to a major city, release the pet, and begin the MMO equivalency of the Black Plague. Luckily, it only seriously affected one server, and Blizzard fixed it. Of note, the same technique of a diseased pet carrier could also be used for several other, much less severe jerk moves (like releasing high level mobs on low level players) but the cake goes to the Living Bomb debuff cast by Baron Geddon in Molten Core which causes the victim to violently explode, obliterating everything in range of the blast. Needless to say, a crafty warlock quickly got his pet infected and released it in a crowded auction house...
 * In what may qualify as a Crowning Moment of Awesome (or at least a Crowning Moment Of Geeky) for the researcher involved, the Corrupted Blood Incident was the subject of an article in the real-world scientific journal Epidemiology, examining the spread of the disease through the virtual world, complete with analysis of the effects of NPC "carriers" and "terrorists" who deliberately spread it for malicious reasons. The CDC contacted Blizzard on the subject. So the spread of a fictional disease among digital characters in a game made it into a scientific journal as a possible model for the spread of real-world diseases.
 * Blizzard later recreated this intentionally as part of the lead-in for the Wrath of the Lich King expansion, introducing a disease that could be carried by players and that would result in transformation into a zombie (who could then infect other players, as well as nearly any NPC in the game they could catch) if not cured by one of many healer NPCs added to the towns for the event. Although many players were annoyed at the disruption - on some servers, the game was nearly unplayable due to the mass infection of service NPCs - the event ran its course as planned. (Popular rumor claims that it ended early because of the complaints; the devs claim otherwise.)
 * As of this edit, there's a bug that if you die, there's a chance your corpse will be in Gavin's Naze in Hillsbrad Foothills. This is especially game breaking when you're on a different continent or world, forcing you to spirit resurrect because of bad game design.
 * This is actually a fix to an earlier bug. Gavin's Maze (or Crossroads for the Horde) is the default graveyard you'll appear at if the server gets confused and can't figure out where you should be. Before this bugfix, instead the server would have you drift slowly in a void with a green vortex-like sky and you would drift slowly through a continent and across the ocean. Since there were no spirit rezzers there, the only way out of this was to file a GM help request.
 * Runescape experienced a fairly game-breaking bug in early 2009 where the game client would immediately crash anytime it tried to display µ (alt code 0181) in either public, private, or clan chat. By disabling all forms of chat, one was able to safely type µ into the public chat and crash anyone nearby (that had Public chat enabled) without crashing themselves. Mass Griefing ensued.
 * Even worse than that is the infamous Falador Massacre that happened (creepily) on 6/6/06. It all started when one player decided to have a party at his in-game house in celebration of getting level 99 in Construction. This, of course, included a combat ring. However, the lag in the house became so severe that he had to kick everyone. The players who had been in the combat ring somehow retained to ability to attack players, so, needless to say, they went on a killing spree, looting millions (in-game) in items. What made this even worse is that the victims were not affected by the glitch, so they were completely helpless, unable to fight back.
 * Global Agenda's new 1.3.2 patch contained a major bug in the auction house that allowed players to effectively create money from nothing. So far, Hi-Rez has responded by banning everyone who has come in contact with the exploit in any form, including people who recieved duplicated cash without knowing that it was effectively counterfeit. There have been accusations that the exploiters started giving away the money to unsuspecting players when it became apparent that Hi-Rez was tracking it, in order to get as many people banned as possible.

Platformer

 * Glover on the N64 has one where you have to throw your ball into a holding tank and then jump into another holding tank and it will rocket you to the other platform. Only problem is, about 75% of the time, you or your ball will phase through the floor and die from it. There is also a point where if you fall off a platform in a certain level, you will glitch through the floor and get stuck there.
 * Rastan on the Commodore 64 is fatally bugged on the second level, it is IMPOSSIBLE to make a jump over a flaming pit over 2 ropes, try it on an emulator with save states and you'll see.
 * The famous Attic Bug in Jet Set Willy on the ZX Spectrum. An arrow that appears on this screen travels out of the screen memory area and into the game code, overwriting it and rendering the game Unwinnable. The first people to beat the game did so by hacking the code.
 * Perhaps for that reason, it became famous as the most hacked game then in existence. A couple of hundred separate hacks were published in various magazines, including one that removed Maria, the housekeeper. (Since the entire purpose of the game was to get past Maria by collecting all the Plot Coupons, this hack made the game pointless.) Even better, there was one that triggered the ending sequence when the player collected the first, very easy Plot Coupon.
 * The programmer of the C64 version fixed the infamous Attic Bug, but didn't finish implementing the final cutscene, and so the game was still impossible to complete. Heartwarmingly, in 2010 a bunch of chaps from the forums of Lemon 64, a C64 fan site, transplanted some of the code from other versions of the game, thus making the game finally winnable. The 27-year-gap between initial release and final patch must be some kind of record.
 * Space Station Silicon Valley on N64 is impossible to win with Hundred-Percent Completion because a required item couldn't be picked up.
 * In Jak and Daxter, a glitch sometimes makes it impossible to win a certain race (the game will expect you to complete a course in 1 second instead of 45), thus preventing you from getting every power cell in the game. The makers of the game apparently knew this, as the number of cells required to get the good ending is one less than the total number in the game.
 * Jak II has a showstopper late in the final act of the game. It seems that playing the optional races in the stadium creates an event flag that supersedes a later story mission. The mission icon appears on your radar, but as soon as you approach the area, it disappears to be replaced by the icon for the optional races you triggered earlier, making it impossible to trigger the start of the story mission. You have to delete the save file and start from scratch.
 * Jak X has an even worse glitch which apparently occurs mostly on black slim PS2s; it's possible for your game save to randomly become corrupt whenever you try to save. If you're lucky, you can overwrite the save and keep going. If you're unlucky, the whole save file becomes corrupt, leaving you with an undeletable file that the game tries to read but can't. There are ways to avoid it, but fixing the latter is out of the question, short of buying a different model of PlayStation 2, buying a cheat device or doing some modding to fix/delete the data.
 * A horrible, horrible glitch in the first editions of  Spyro: Year of the Dragon prevented you from gaining the second egg of the first world's Speedway level if you exit the level without getting it, even if you didn't even select the objective needed to get it in the first place. Even if you do win the race needed for the egg after this glitch is triggered, it won't register, preventing One Hundred Percent Completion.
 * The game's own difficulty system led to a borderline example. On Fireworks Factory, a pair of ninja opponents are present on all difficulty levels, but on Easy they don't jump down to fight Spyro. It's necessary to fight them for two gems. It is fixable by using a cheat code to change the difficulty level or by playing well enough for the game to change the difficulty itself, but unless you know how it can be a game breaker.
 * A rather irritating glitch can sometimes occur in Dawn Of The Dragon, where even if you've completed the game, and collected everything/defeated all the Elite Enemies/upgraded all your elements to their maximum, the file will only read 99%, meaning you can't open the final gallery.
 * The Sonic the Hedgehog games have a few of them, most of which are caused by Sonic going so fast he breaks the game. In the first game, you could die by going too fast for the screen to keep up (because it just kills Sonic when he touches the bottom of the screen), and there are other situations where you can get stuck in the scenery and be unable to get out. The American Manual for Sonic 3 actually acknowledges that it's possible to get stuck in scenery during Mercy Invincibility (and be forced to either wait for a Time Over or reset the game), but handwaves this as a "diabolical trap" left by Dr. Robotnik.
 * An additional glitch in Sonic The Hedgehog 3; in Marble Garden, while playing as Sonic with Tails, you could actually scroll Tails off the screen permanently. While this would be good (since Tails is a Stop Helping Me! annoyance in this mode), it also prevents him from showing up during the end-Zone boss, a boss that requires you to have Tails fly you up to meet. This means you're permanently stuck off-screen and unable to complete the game.
 * Another fun glitch at this point. By this time you could be playing as Super Sonic. During the Robotnik animation where he is demolishing the scenery just moments before the boss battle, it is actually possible to damage him. Well...just try and hit him 8 times. GAME CRASH!
 * This Youtuber has analyzed an incredible number of bugs in Sonic 3 & Knuckles in all stages. The worst cases cause the game to crash; the silliest cased cause the game to restart.
 * The Quiz Lady bug in Sonic Unleashed. Essentially, this bug will cause Sandra--a woman who travels around the world, giving you quizzes about the place you meet her in--to not appear in Shamar. Therefore, you are unable to finish this quest, unable to get the Art Book she hands you for finishing, and therefore unable to get 100% completion. You get this bug? Too bad! Looks like you'll have to start a whole new save file. This has since been fixed…at the cost of about 250 Microsoft points to get the Chun-Nan DLC.
 * The first Sonic Adventure had Game Breaking Bugs that doubled as Good Bad Bugs, and vice versa. These bugs allowed characters to access levels or parts of levels that they normally couldn't, and could also access stages out of order. However, doing this could cause glitches that, at best, made the level unbeatable, and at worst, made the game unbeatable. One of these is the bug that allows Knuckles to enter Casinopolis early. While you can play through the level without a incident, the problem occurs when you beat it; Tikal whisks Knuckles away to the past . . . and he's stuck there. The game doesn't necessarily freeze, as Knuckles is still able to move around and explore. However, Tikal and her father are glitched in a way that has them standing in midair. This prevents the cutscene that ends this sequence from playing, making it literally impossible for Knuckles to ever leave the past.
 * Let's not get started with Sonic the Hedgehog 2006...
 * Shadow the Hedgehog has a bug in The Doom stage. Playing the dark mission requires you to kill all GUN Troops however one specific area the final mech that you are required to kill in order to complete the mission will not spawn without you backtracking to a previous checkpoint. This added to an already ridiculously expansive and maze like level.
 * Harley's Humongous Adventure on the SNES has a nasty tendency to crash by merely jumping or walking to certain locations during normal gameplay.
 * In the Genesis game Garfield: Caught in the Act, occasionally the third boss would walk off the right side of the screen and never return, forcing the player to restart the game and start all over.
 * The Prince of Persia "Sands" trilogy had some pretty weird bugs throughout the games.
 * One in Sands of Time would stop the platforms in the observatory from correctly lifting (may have had something to do with Farah triggering the switch instead of the player). A more infamous one occurred in Warrior Within, where the game would randomly teleport ahead when loading to a part far later, . The only way to fix it would be to load an earlier save. Don't have one? Sucks to be you!
 * Then there was a horrible bug right at the end of the game where you'd try to run through the last sand portal to face the end boss and the portal would simply refuse to work. We still have no idea what causes it so your best bet? Play the entire game over from the beginning!
 * SOLUTION! It involves the life upgrades. You MUST get the upgrades in a different order than you are presented with availability to reach them in game. This means that as soon as you could reach the upgrades, you must not get one, returning when you are at the end of the game, before going into the final boss room.
 * As of this posting, it is certain that skipping the first upgrade, as you enter the castle, and returning just before the final boss, WILL make this bypass the glitch. Unknown if other orders will work.
 * Another oversight allowed you to reach an unreachable door and bypass a decent chunk of the game. Said occurrence forced you to run a massive disintegrating obstacle course, only to arrive at a wall which can only be broken with a sword you don't own yet. And unless you avoided the two saves along the nigh-impossible road to failure, you were forced into starting a new game. Worse still, you can stumble into this by complete accident with no indication.
 * And then there's ‘’Prince of Persia 2: The Shadow and the Flame’’ on the Super NES. One specific standard enemy, when killed, crashes the game. Then again, it can be argued that the port is a giant bug with bits of game in it.
 * In the often loathed "Prince of Persia 3D", there was a spot late in the game where a moving platform would not be moving. It causes excessive frustration the first time around, since the player has no idea it is supposed to move. To make matters worse, once the player reaches the area, the platform will not move unless the level is restarted and the player gets lucky.
 * Not a Game Breaking Bug in the true sense of the term, but one that applies to One Hundred Percent Completion. In the original N64 version of Banjo-Kazooie, all items collected in a level except for jiggies, Mumbo tokens and extra honeycomb pieces would reset upon the player dying or leaving the level. The team that ported the game to Xbox Live Arcade changed this so that both notes and jinjos would be saved by the game's autosave feature. The problem with this is that there's a mini-game in which you have to do a jigsaw based on a moving image of Banjo exploring an area of a level, and the moving image was made using the in-game engine. What this means is that if the jigsaw-Banjo picks up a note in the N64 version, it resets afterward, but if he does it on the XBLA version, it's Lost Forever and isn't added to your total. Infuriatingly, there's achievements for completing all the moving image puzzles and for getting all 900 notes, meaning that if you didn't complete the whole game before doing the jigsaws you'll have to start again right from the beginning if you want the last achievement. The real kicker in this whole scenario? A month after the glitch was first reported, a patch was made to fix it...and it didn't work for existing saves. You had to restart the whole game to get 100%.
 * The NTSC Atari 7800 port of Impossible Mission has a bug that made one of the puzzles literally impossible to complete. This was fixed in the PAL version.
 * In Sly 2: Band of Thieves, saving and quitting during the Canada Games section of of the game makes it impossible to complete the level, rendering the game Unwinnable. This has a fix built-in, though you do have to backstep a few missions. Just head to the house that contains the safe, and head to said safe. Once Jean Bison yells at his lackeys, you should be able to pull a switch and redo the laser mission.
 * In Mega Man 4, if you time a Rain Flush so that it goes off while Wily's escape pod is on the screen, it will destroy it. However, the victory music and the lead-in to the final stage will not play if that takes place, meaning that you have no choice but to restart from the last place you wrote down the password for. Thankfully, this is more of a deliberate undertaking than an accidental one. There is a similar bug in the original Mega Man, where if you get hit by the final boss just as you defeat him, the screen will glitch and the game will never proceed to the ending. The only remedy is the reset button.
 * A similar glitch occurs if you use Flash Stopper to finish off the third Cossack boss: The game will never proceed to the next stage. Thankfully, Flash Stopper is useless against this boss anyways, and there's a bed of instant-death spikes in the room.
 * Little Big Planet has had several of these:
 * Least severe was the terrible, horrible server lag that was apparent for the first few months of the game, rendering it nearly unplayable online, despite the online connectivity being one of the main points of the game.
 * Many players encountered a bug that, when making a large grab-able material spin extremely fast in the level editor and grabbing on, they would no longer be able to respawn, stuck on some sort of infinite pseudo-death loop. Returning to the pod (main menu, basically) continued this, and this persisted even upon resetting the game, rendering the game completely unplayable for those affected. The only way to undo this was to delete the entire save data.
 * The "moon" on the right, which gauges your Play, Create, and Share points (among other things) is completely non-operational, and has remained this way to this day (curiously, it was working fine before the official launch, I.E. before the servers were up).
 * Still prancing around is the bug that makes your file completely unable to save new data (and gives no error indicating this. The game only autosaves), apparently brought on by having too many custom/community objects, and it supposedly fixable by deleting all of that and avoiding community objects like the plague. Obviously nobody wants to do this either.
 * A PlayStation 2 demo version of Viewtiful Joe 2 had a severe bug that caused all other data on the memory card to be erased by just playing the demo.
 * In the PC version of the 1994 platformer Lion King, the second level requires you to roar at some monkeys so that you can get them to turn around, allowing you to solve a puzzle. Unfortunately, 90% of the time you enter this level, a bug manifests where your "roar meter" never fills up, thus making it impossible to affect anything with your roar.
 * LostWinds is unfortunately affected with a bug where Toku occasionally gets stuck in the ground after a long fall. Effects can range from him being unable to jump (either over small ledges or with Gust) to being completely stuck. Sadly, the only way to get out is to reset. If you haven't saved recently, sucks to be you...fortunately, the game does autosave at various points in the game, and the game is short, so even if you don't use the save pillars, you'll probably never go that far back.
 * The computer game Jazz Jackrabbit had a bug or level design error that allowed you to get stuck in walls and ceilings, either by jumping or being spring-boarded into them. The cheat code for teleporting could also transport you into them. With cheat codes, it was possible to escape; otherwise, all you could do was restart.
 * A worse one in some of the builds of the first game made one of the levels in Oribitus nigh impossible to beat. The level featured bouncy walls and a bouncy floor that also, unfortunately, acted at a ceiling that sucked you up to the level above if Jazz so much as scraped a hair on it. Add in a few tiny holes the player has to navigate to without touching the floor or ceiling makes for a recipe of pain. Players attempting this should turn on slow motion mode, as it's unwinnable otherwise.
 * The Wizard of OZ platformer on the SNES. As stated by The Angry Video Game Nerd, one glitch that defies all gaming sensibility is the fact that you fall off any platforms that you try to jump on unless you land perfectly dead-center.
 * An extremely serious glitch can occur in Donkey Kong Country 2 on the vertically-scrolling Castle Crush stage. There is a barrel near the beginning which can be grabbed and broken without being thrown. A demonstration of the glitch can be seen here. The glitch can cause the game to crash in some cases, but this could end up being worse than a simple restart or even losing save files (which is another potential result of the glitch). In some cases, the glitch's effects are so severe that they damage the game beyond repair. An example of the broken ROM can be seen (here). Some accounts suggest that this damage even extends to the system or emulator itself. The same issues do not appear to occur in the Virtual Console version.
 * Donkey Kong runs into these nasty glitches more than once. This video shows a number of glitches from the first Donkey Kong Country game, most of them harmless, but the one starting at 8:47 is decidedly nasty. Rambi gets glitched as the cave is opened, and the game freezes when he tries to exit. On restarting, the environment is a mass of flashing error, rendering the game utterly unplayable. An ominous annotation near the start of the segment says the glitch was tested in Super Nintendo and altered the system - whether he's just talking about the emulator or if it was tested on an actual system is unknown. Fortunately, unlike the Castle Crush glitch from the next game, this one requires enough set-up as to almost never happen by accident.
 * In Donkey Kong 64, there is an obscure bug with the "Sneeze Alert" mechanical fish in Gloomy Galleon. If you get the Sniper scope late in the game, then later go to the fish, the spinning fan lags, but not the timer. This makes the Golden Banana here impossible to get at this point. There is a workaround, where you can disable the Sniper scope while you are waiting for the fan to finish spinning, but due to the sheer obscurity of this bug, most people won't know to do this at all.
 * In Super Mario Bros. Deluxe for Game Boy Color, if you earn the Yoshi Medal at the same time as the Red Coins or High Score medals in Challenge mode, you'll only get the Yoshi medal, and the others will be Lost Forever.
 * In the earliest copies of Rayman 2 for the PC, at the beginning of the level "The Top of the World", a message will pop up telling you the CD is missing and that you have to insert it to play on, even if it's not. The worst part about this is that the message features a huge picture of a robot pirate's face, so it's pretty much a screamer without the screaming. Nightmare Fuel, anyone?
 * In Mega Man ZX Advent Model P has the ability to grab ledges. Unfortunately, it also has the ability to grab the ceiling. If this happens, you can't let go or transform, leaving you with no option but to turn off the DS.
 * Unless there are some copies of the game that aren't functioning properly, all you ever had to do was push the jump button while holding down to let go of the ceiling, just like you would in the first ZX.
 * In Cool World on NES there's a glitch where if you manage to store up at least ten lives and then die it's an instant game over.
 * Due to a poorly designed physics engine, some levels in Super Meat Boy are literally impossible when playing on a slow computer. This can be mitigated to some extent by switching to a lower graphics resolution, but if it still isn't fast enough on 640x480, you're out of luck. Hope you weren't planning on ever seeing 2-18x.
 * Home Alone 2 for the NES has a fatal bug where, if you manage to get through the game with the Bell item intact without getting hit and spin jump into Marv or Harry in certain parts of the third level, the game freezes.

Real Time Strategy

 * An insidious bug in the Warhammer 40000: Dawn of War: Soulstorm expansion lets players queue an upgrade and cancel it to receive their investment back. Which would be a good thing...if the upgrade's price didn't increase in the meantime, thus resulting in infinite resources in multiplayer. Hilarity usually ensues. The first problem with this bug was that it took Relic over half a year to patch. The second problem was once they patched it, they replaced it with an even worse bug -- the Sisters of Battle armour upgrade applied itself to all their units rather than just their infantry (and applied itself to their infantry twice). At least you had to choose to use the infinite resource bug.
 * There's another bug that you can use to screw over the AI in single player while playing Orks, in which saving and reloading causes the game to forget how many troops you actually have and start thinking your whole 100-Ork-resource army has only 24 Orks in it, allowing you to build another 76 troops.
 * There was also another bug that allowed spectators to activate a Dark Eldar player's Soul Powers. While this was more annoying than fatal; it was still a ridiculous oversight that led to severe annoyance on the part of DE players.
 * The Horde for the 3DO was infamous at the time for deleting all your save files of other games. A fixed version was released after great outcry.
 * Command and Conquer: Tiberian Sun had a rather useful bug (for single player) which turned really bad in multiplayer - for your enemies. If you play as the GDI and build so-called Firestorm Walls, you can activate these via ability and they become fully indestructible to anything, even superweapon strikes, they block all weapons (except your own) and also force aircraft trying to fly over them to crash into the ground. Normally they deactivate and have to be recharged after some time of use, but when selling enough powerplants while they are activated so your radar shuts down...they stay active. Indefinitely. You can bunker down and wait until your enemy gets annoyed and quits. There is nothing (s)he can do but try to destroy the special generator structure powering the walls with a superweapon - which is impossible since the structure has more health than any of the superweapons does damage.
 * Similarly to the XCOM Terror From The Deep example below, UFO: Aftershock has a particularly nasty bug that prevents one of the research topics from appearing, making the game Unwinnable. It was never patched - instead, you had to e-mail your save to the company to fix it. The company went bankrupt. Now the only way of fixing this is finding the forum post that describes editing your save with a hex editor to trigger the appropriate flag.
 * Aftershock can also uninstall anything that runs in the background.

Rhythm Game

 * DJMAX Portable Black Squares and Clazziquai Editions background music have a bad habit of skipping and desynchronizing every now and then. In a Rhythm Game, this is a big problem, as it can make the song more difficult to play. Although some have fixed this problem by using the "Data Install" feature (which installs some of the game's data onto the memory stick to reduce load issues regarding the UMD). On the other hand, playing the game via an ISO on a memory stick circumvents skipping--an unintentional punishment for those who play DJMAX games the legitimate way.
 * The arcade version of Beatmania IIDX 9th Style has a bug in which starting up the song "Quasar" will sometimes cause the game to freeze, forcing a reboot. Additionally, after rebooting, selecting a certain song as the first song since the machine's reboot will trigger a hilarious bug in which you cannot get any note judgments other than POOR, making the song Unwinnable. To be fair, 9th Style was the first version of the game to run on a PC-based system with Windows XP Professional instead of their legacy "Twinkle" hardware. Later versions (which also soon switched operating systems to Windows XP Embedded) would have fewer of these glitches...except for one:
 * The song "GAMBOL" had a history of having completely broken timing windows. On 12th Style (Happy Sky), this was finally fixed...by putting a fixed chart on the Normal difficulty and keeping the broken version as an Ascended Glitch on Hyper. The joke got taken Up to Eleven on the console version of well...11th Style, by making an even more broken version on Another.
 * Guitar Hero 5 has the Expert/Plus bug that affects double-bass sections on songs with Expert+ . specifically, every other kick of a double-bass run in Expert+ would be a "null" kick in Expert. This is most noticeable on Done with Everything, Die for Nothing, the song with the fastest double-bass run on the disc. Neversoft also fails to see what the problem is, since they can clear the chart with 92% notes hit.
 * The home version of Dance Dance Revolution Extreme failed to add the "Dance Mode" controls to the options screen. Thus, the corner squares on a dance mat would also trigger arrow presses as if you were playing on a handheld controller, making it essentially impossible to play the game as intended (certainly impossible to play it well).

Role Playing Game

 * Fallout had its share of minor bugs, but the second in the series, whoo boy. The car seemed to be a Bug, and not in the 'small German vehicle' sense. It would end up stuck in the exit grid, making it unusable, as you couldn't reach it to drive away. In a particular mission, it would block the exit and prevent a load of freed slaves from escaping the map, and again preventing you from being able to use it. Occasionally the trunk would detach and follow you around; the rest of the car just vanished.
 * The initial PC release of Fallout: New Vegas was prone to random crashes from the start of the game. But the Game Breaking Bug part was that quicksaves were corrupted and would only load the very first one the player made (usually in the starting town). This meant only autosaves (from entering or exiting a building or location that brings up a loading screen) and regular saves could be used to recover your game if it crashed. Hope you didn't like quicksaving.
 * The Elder Scrolls: Arena and Daggerfall are exceptionally buggy games; their stability is alleged to be different between different start-ups, between different systems, and between different installations on the same system. Inherently, both games suffered from broken quests, garbled dialogue, texture loading problems, item and enemy failures, unloadable saved games, audio-induced crashes, and nonfunctional features; the latest (last) patches for each respective game, including save state and quest fixer programs, make the games workable but leave many errors.
 * The infamous Void, introduced in Daggerfall and featured in many other The Elder Scrolls games, is a consequence of 3D gaming - an expanse of emptiness that existed outside of the game's standard corridors. What makes the Daggerfall Void (in)famous is the frequency of the player's helpless fall into it. One of the many tunnels in plot-relevant dungeon Castle Daggerfall ends abruptly on an opening into the Void. Given that Castle Daggerfall houses the MacGuffin central to the plot, you'd think it was one of the few of the thousand or so dungeons where designers would catch that.
 * The auto-dungeon generator in Daggerfall was so buggy that Bethestha finally just threw up their hands and released a patch that turned on the debugging shortcuts-- so affected players could teleport around dungeons and avoid falling into the numerous bottomless pits.
 * In the XBox version of The Elder Scrolls: Morrowind (the Game of the Year edition), annoying glitches prevented one from using most of the added features. The quest chain in which the player gets turned into a werewolf would not progress after a certain point. Going for Vampirism afterwards would allow one to complete a few quests for the chosen vampire clan, but the keywords to get the next quests didn't show up.
 * The Elder Scrolls IV: Oblivion also has its fair share of bugs, but one notorious one in the PlayStation 3 Game of the Year version rendered the state of Vampirism to be incurable because a certain Event Flag during the Vampirism Cure quest failed to work properly. Strangely enough, this bug appeared in the original versions for the PC and 360 and was quickly patched up, while the PlayStation 3 original version released a year later did not have the bug. This makes people wonder what the developers were thinking when it was somehow re-introduced in the Game of the Year edition.
 * A rather lethal but nevertheless hilarious one is a bug (has been fixed by official patch) where any item stolen by a female character automatically loses its stolen tag, meaning it no longer counts as stolen and can be sold to any honest merchant, this breaks the Thief's Guild quests as it requires you specifically to sell "Stolen" goods. The Double Standard implication can't help but make some wonder whether such a quirky bug was really by accident.
 * And then we have the infamous Abomb bug. This is a particularly malevolent and soul-crushing one, as it kicks in after you played for hundreds of hours (which is very easy to do in a sandbox game, especially one with as much stuff to do as Oblivion). When it triggered (yes, WHEN, not IF - it's inevitable and can't be fixed on consoles), effect animations like fires, lighting or, say...doors opening, would either slow to a crawl or stop executing entirely. This, among other things, caused dungeon gates and Oblivion gates to stop working altogether...which has predictable results on the playability of the game. The worst part? Bethesda KNEW the Abomb bug existed - they found out during a contest to see which player could play for the longest time. They did NOTHING to fix it. For shame...
 * The Elder Scrolls V: Skyrim shipped with a rather nasty bug on the PlayStation 3 version, where the game discovering new locations put the data into your save file, bogging it down. If you've filled out your map, the save file will either be unplayably laggy or simply refuse to load at all. The PC version also has a rather frequent issue with graphics glitching out just preceeding a crash the next time the game would load up. Bethesda fixed the former, but their attempts to fix the latter has actually increased the frequency of the crashes on some systems.
 * Super Paper Mario had a glitch that froze the game if you did some stuff out of order. Not Sequence Breaking, just completing some tasks without talking to someone nearby who specifically tells you to do them. Since the Wii doesn't do downloadable content and patching very well, Nintendo just let people swap for a patched disc if they really wanted to.
 * The original Paper Mario also contained a game breaking bug in Bowser's lower area of the castle. There was a room containing an item that was supposed to only be accessed after getting rid of the lava. If you tried to jump into the entrance of the room, what would happen is, the lava will damage you, sending you up in the air as usual, but afterwards, you would trigger the "enter area" script. It would show the room in lava momentarily, then the game cuts sound and practically implodes, and you see countless numbers pop up.
 * The Japanese version of the DS remake of Final Fantasy IV had a glitch where, if you played a certain video from the Fat Chocobo's video viewer menu and saved afterward, the player would actually gain control during the ending sequence, and the game would never actually end. Thankfully, this was fixed in the Western releases.
 * Final Fantasy V had a weapon that would sometimes make you run away from battle instead of doing an attack (the Chicken Knife), and a class that could not run away from battle (the Berserker). If the Chicken Knife's effect triggered from a Berserker attacking with it, the battle would keep going, but neither you nor the enemies could actually do anything to each other. The only way out of this one was to reset your game. Better hope you saved recently. To make this one even more annoying, the Chicken Knife could easily be one of the most damaging weapons in the game. Thankfully, this bug was fixed for the Advance version.
 * Similarly, the original release of Final Fantasy VI had the infamous "Sketch bug" -- one of your character's commands, when it failed, would have unpredictable results, often rendering the game unplayable. This was quietly repaired, and most cartridges of the game don't have this particular error. The game does have other bugs, but thankfully, they're not as severe or as easy to trigger. Of course, if the game didn't become unplayable after that, you could end up with a bounty of items. Beware using "Sort" afterward, though, because you can lose items in your inventory. The 1.1 release fixed the bug with an Obvious Rule Patch that can be disabled with a single Pro Action Replay code.
 * You can't get Gau out of "Rage" mode once you've chosen that command, so it's possible to trigger an endless feedback loop. Namely, if you choose to have him imitate a monster that attacks with fire and is healed by it, and if you go up against an enemy that does the same, you'll keep attacking/healing each other forever until you finally reset the game.
 * The original Japanese version of the game supposedly has a bug late in the game that lets you return . No points for guessing whether or not you can get back.
 * The Greatest Hits release of Final Fantasy Chronicles (which includes Final Fantasy VI) has a bug that can render the opera scene Unwinnable. You're required to have Celes and Locke in your party for the scene, but the game doesn't lock them in your party; it only locks the characters in the first two slots. So, make a party, switch them around so Celes and Locke are on the bottom, and make a new party. The only problem is, to switch party members again, you have to go back to the house in Narshe and talk to one of your other party members. Celes and Locke aren't programmed to show up at the house, parties contain four members, and you only have six characters available; making a full party that doesn't include Celes and Locke, then saving, makes it forever impossible to put them back in your party.
 * It is also possible to render the game unplayable by having a party with nobody in it. This can be done via a somewhat convoluted method of making a party containing only Gau, after the battle at Narshe when everyone splits up to look for Terra, and then joining up with Shadow, who will appear in Kohlingen if there is an empty space in your party. Then travel to the Veldt, have Gau Leap on an enemy, leave before he returns, and take Shadow back to Narshe alone. Upon entering the town, he will spout one of his "my job is done" lines and leave, which happens every time you take him there during this part of the game, but since he's your only party member, it will then become impossible to continue in the game. (You can, however, bring up the status screen and see your empty party. The game will crash when you exit the status screen, though.) Demonstrated here.
 * Makai Toushi SaGa, released in the US as The Final Fantasy Legend had a lot of strange bugs, including warps, area glitches, character corruption, extreme increases in travel speed, and a one-hit-kill that works even on the final boss, which when exploited ruthlessly make it possible to finish the game in under two minutes. That's less time than the ending credits take.
 * In Star Ocean: The Last Hope, sometimes when the player or the CPU-controlled partner casts the spell Silence on an enemy, if the spell misses, "Miss !" will remain displayed on the top of the foe until the battle ends, and after that, the game freezes, forcing the player to reset. Fortunately, the player can manually prevent the IA from casting that spell, which is a Useless Useful Spell anyway. In the PlayStation 3 port of this game, the glitch still remains. It was also reported that playing the PlayStation 3 version with the Playstation Network still running in the background occasionally freezes the game, so the player better has to play the game 100% offline, as it doesn't feature any online mode anyway.
 * Early versions of Neverwinter Nights 2 had a cutscene that would repeat constantly in one area, with only one round of combat in-between "cycles", taking forever to finish one boss fight. This was fixed in 1.06 and later.
 * The game had several other popular bugs -- characters disappearing and being unrecoverable, forcing you to reload an earlier save; the game crashing after you try to leave the Sunken Flagon; the skill point distribution screen not loading, keeping you from levelling your characters (and I defy anyone to do a Low-Level Run of that game). Evey bug reported gets the same standard response on their forums, too -- run the updater. Doesn't matter if you're patched to the latest version of the game.
 * NWN2 can also "lose" the targets for its area transitions, resulting in your party being stranded in an area and unable to progress through the game. Complete uninstall/reinstall and patches do nothing to fix this. Users must mod the functionality back in.
 * And there's also the fact that randomly, your party members will get frozen into place, and thus they can't assist you when you're attacked. Sometimes it's fixed when you move to the next area, sometimes they're just stuck in that next area.
 * NWN2 bugs out in a dozen different ways if you patch it before installing the expansion(s). If you uninstall, re-install, add expansion(s), and then patch it works (and savegames can be successfully backed up).
 * The worst for NWN2 has to be the second expansion. If you install it after the MOTB expansion, it will erase all of the sound files for MOTB. This renders the MOTB campaign unplayable, and the patch to fix it is almost a GB.
 * The thid Expansion got its own share of bugs as well. Mainly the installer. The copy protection of the first discs that were produced were quite vigorous in their protection, causing you to be unable to install the game because it would not recogniue the original DVD in your drive. Of course by then it would cancel setup and wipe out the files it tried to patch, causing the Main Game and the first expansion to be unplayable as well.
 * Similarly, Titan Quest has a bug which causes your computer to bluescreen, restart, and destroy your character. Thankfully, a backup is saved each time you quit.
 * In the PC/Xbox 360 adventure game Two Worlds, save files made before the most recent patch would not be able to get the achievements Visit All Locations and Visit All Undergrounds due to a glitch that occurs when a player attempts to enter Beaver Kettle Cave. The player attempts to enter the cave and is suddenly warped across a fairly large river quite some distance away from the cave, and is therefore unable to unlock the cave on his map.
 * Similarly, at launch it was possible to make the game Unwinnable. If one were to steal from a town or attack someone, the townsfolk would rebel and there was absolutely no way of calming them down apart from killing them all. If left to their angry ways, or if left for dead, this could possibly interrupt questlines required for the story and make it impossible to finish.
 * In the PlayStation 3 version of Two Worlds 2, there's a glitch in the staircase in one of the Thieves' bases. If you walk next to the stairs and turn back, you fall through the floor into some kind of glitchworld. The thieves can still attack you, but you can't see them, which is pretty annoying. You do get some nice views into the walls though.
 * In Star Ocean the Second Story for the PS1, if the player presses ANY buttons while switching from the 'battle complete' screen to the field screen, you get the Blue Screen of Death. Particularly interesting if you're in the Secret Dungeon, which has ZERO save points. There are other various glitches, but this is the most prominent.
 * If you were in the battle arena and used a Lunatic High, (an item which canceled player control) on a character you had set to "Avoid Enemies", they would continually evade the enemies with no interest of taking or dealing damage, forcing you to restart
 * Almost all of the infamous "Glitch Pokémon" in Pokémon Red/Blue that the normal player will encounter are more or less "safe", despite their infamous effect on the player's Hall of Fame data. However, by using the more complicated "Mew Glitch", it's possible to encounter glitched Pokémon -- and glitched Trainers -- who can severely mess up in battle, crashing your game. The upside is that the crashes are frequently so spectacular, they might just be worth seeing anyway.
 * Probably the best example is the hang that occurs if you encounter a ♀. In theory, the battle might just go fine -- but we'll never know, because ♀'s cry never completes. The music code that gets loaded is an infinite loop. The cool thing is that it doesn't sound like an infinite loop, because it actually spans portions of the audio chip's RAM, which can get changed between cycles.
 * While it doesn't actually destroy your game, performing the infamous Surf glitch incorrectly can lead to getting stuck forever and forcing one to delete their current file and start a new file. Or use PokéSAV to edit their current location; whichever works.
 * Actually, even some of the "standard" glitches can erase your file depending on what you do with it. While Missingno. is entirely harmless, 'M can be dangerous if you catch it at Lvl 0 and it goes to your computer instead of joining your party (if you try to take a Lvl 0 'M out of the PC, the game crashes). Apart from that, they mess up your Hall of Fame data and nothing else, but the other, lesser known glitch Pokémon can eat your game data.
 * Removing any Lvl 0 or Lvl 1 mon out of the PC crashes the game. Lvl 1 mons can be encountered by using the Mew glitch, and using Growl six times in the encounter just before triggering the glitch encounter. (The glitch encounter's level is set at 7, ranges from 1 to 13, gets decremented by Growl, and gets incremented by Sword Dance.)
 * Also from Pokémon, saving in Glitch City without a Pokémon who knows Fly renders you trapped forever and the game Unwinnable.
 * In some versions of Pokémon, there was a rare bug that made the game ignore the most recent save and revert to the previous one. This meant that the player had to save twice to ensure that he/she would not lose progress. However, beating the Champion of the Elite Four caused the game to save once, and then automatically reset, taking the player back to the previous save in an endless loop and making the game Unwinnable.
 * In Japan, Atelier Liese shipped with an absolutely terrifying number of game-wrecking bugs; it was the worst QA job in Gust Inc.'s history. The full bug list is available here (in Japanese). A corrected version of the game was shipped out, but by then the press had already eviscerated the game publicly.
 * The PAL version (or at least, some versions of the PAL version) of Atelier Iris [[Eternal Mana]] had an irritating bug right at the very end of the game where it would crash during the ending sequence. This was doubly annoying as not only was it impossible to see the entire ending, but you also couldn't get a completed save file as a result, preventing you from playing the New Game+.
 * Kingdom Hearts: Birth By Sleep has a rare glitch during Aqua's fight against Maleficent: at times the fire the boss causes on the bridge won't go out, killing Aqua if you do nothing.
 * In Tales of Symphonia there is a curious glitch where if you screwed up during a puzzle in one dungeon a bolt of lightning would move you partially into a wall, and you won't be able to move.
 * In Tales of the Abyss, there is a truly amazing glitch where, if you were to remove the disk from your PlayStation 2 while in the overworld, and run around a bit, the land would give way and you could run infinitely in any direction, and you could concievably go ANYWHERE. This leads to easy gets of, if exploited early, some very high-level equipment, making the game ridiculously easy until that equipment is outdated. However, it is possible to replace the disk, making you drop back down to the ground, in the ocean, a river, in a city, on an edge, or in a mountain, and be unable to move, thus making you reset. Still worth it early on, given you save before trying it.
 * Ultima IX: Ascension has too many to begin listing here. Although it also had a few Good Bad Bugs, the genuinely bad ones far outweighed them. Some of the bugs make for a very surreal experience, such as crossing the ocean on a bridge made of bread.
 * Wild Arms: Alter Code F had a bug where sections of the overworld would randomly blank out, to be replaced by ocean. You could very easily just get stuck in the middle of it. There were actually a couple of workarounds: you could keep running in place to eventually trigger a battle, or save via Gimel Coin and reload. Either one would bring back the piece of overworld that disappeared. That said, this was a nasty bug in the Japanese release that people hoped would be fixed in the North American release -- two years later. It wasn't.
 * The PAL release of Wild Arms 4 had a bug that made it impossible to proceed at one point in the game if you were playing in PAL display mode. However, it can be easily worked around by switching to NTSC mode until you're past the aforementioned buggy point.
 * The English release of Ar tonelico II: Melody of Metafalica has a big one during the last fight against in the final area of the game. On her sixth action, if you haven't dealt about 80% or more damage to her, she is supposed to use an attack called "Fractal Change", which does a random Jamming effect out of the four. However, due to a bad string somewhere in between translation and making the final copies, the game simply freezes up. It would be okay if it was any other boss, but this is the optional boss, which must be defeated fifteen times for Hundred-Percent Completion. There have been workarounds (from taking advantage of another bug to just outright patching and hacking), but this is on every single copy released in the U/C region. Oh, and NISA's response? Either level enough so that you can beat enough shit out of her to prevent the turn 6 freeze, or just beat all the shit out of her outright before the attack even comes. Replakia works wonders, but it's not a miracle worker, NISA. It seems They Just Didn't Care when they translated that game. Supposedly, the EU version fixes this bug.
 * You can fix this bug with an action replay and allow her to use that attack properly. Hah, a cheating device to make the game play properly
 * Save with any unpurified firefly cocoons in Jade Cocoon and quit, you'll reload the game to learn all their magical abilities are Lost Forever. This can become a Good Bad Bug if you know how to handle it, as your own monsters won't have their abilities overwritten by the depowered monsters but will still benefit from their stats.
 * In the obscure 1997 Macintosh-only game Task Maker, a starving player will eventually die and be sent to Hell. Unless the player can find food very fast, he will get stuck in an infinite death loop. This carried over to the 1998 sequel The Tomb of the Taskmaker, which never made it past version 1.0 due to the developer's collapse. It was finally fixed when one of the programmers released an update on his homepage...in July 2008.
 * In Final Fantasy I: Dawn of Souls, the Whisperwind Cove has exactly one floor where you can get the Angel Ring: the 33rd basement. However, the Angel Ring can only be obtained if you're on a floor that has 10 chests, and the only floor that will yield this many chests will never be selected as the 33rd basement. As a result, the Angel Ring is unobtainable.
 * Some versions of Chrono Cross contain a bug near the end of the first disc that causes the game to freeze...in the middle of a cutscene that introduces a really important plot point...right after an extremely difficult boss fight.
 * In the first Mega Man Star Force game, it was possible to get stuck between an NPC and a wall. If you did this while not on a Wave Road, the only way to get out was to reset and load from your last save, and hopefully you knew better than to save while stuck. Later games fixed this problem by briefly allowing you to run through NPCs if you get stuck.
 * Champions of Norrath had a pretty serious one. Several hours into the game, your character gets an escort mission to rescue an NPC from a jail cell and have him follow you back to town. Simple, right? Not when the game loads that scene with the NPC embedded inside a wall so he can't walk. Restoring from an earlier save might fix the problem.
 * Icewind Dale II has nasty bug in the Black Raven monastery. Any characters crossing a certain door will not be able to leave the room. If you don't have an old save of game or a specific item that can teleport you out, you're screwed. Thankfully if the player enables cheating it is possible to escape with the teleport command.
 * Mana Khemia Alchemists of Al Revis has this in the bonus dungeon. Any monster past a certain floor except the bosses have a high chance of freezing the game over any little thing either they or you do, combined with how long a fight with them can be due to their insane stats and it is pure luck if you can get 100% completion. Also in part 2 there is a bonus boss in the first chapter on your second play through who has an attack that freezes the game as well. As with the Ar tonelico II: Melody of Metafalica example above, NISA is very bad at playtesting their localizations.
 * Also in Part 2, a glaringly obvious bug in the Extra Scenario, where . While encounterable if you chose Raze first, it's especially apparent if you chose Ulrika as the first character. Having Ulrika read an entry on the Job Board or even going into the Job submenu in the Student Handbook during this Scenario will freeze. Fighting an optional mark in the second scenario will freeze like Raki does - but on the first attack. Thankfully, at that point, you have a load of fresh items with which to lay the smackdown on. A harder one to find is in Puniyo's last Character Quest, where you get up to three Punis in your party. Using a Finishing Strike with a Puni will freeze the game.
 * Nostalgia has a particularly painful one of these, known by fans of the game as simply the "Albion glitch", after the Sequential Boss it affects. Roughly two-thirds of the way through the game - fifteen to twenty hours in, depending on how many sidequests you take on - you fight Albion, a dragon, in your airship...after which he demands you face him without the "help" of the airship. Upon landing, he's supposed to appear and you're almost immediately taken into the boss battle...except that in a large number (somewhere between a third to half) of US-released carts, this second battle simply doesn't trigger, leaving the game completely Unwinnable. And unlike most bugs of this type, this isn't fixed by starting a new game. If the Albion glitch occurs, the only solution is to get a new copy of the game.
 * Mega Man Battle Network 5 had a nasty bug that would render you unable to plug-in or start a Liberate Mission (both vital to storyline progress) after the end of a Liberate Mission if the last two digits of your maximum HP in hexadecimal format were 01 or 02. For example, if your max HP was 2562, in hexadecimal it would be 0A02, which would trigger the bug. Meanwhile, a max HP of 306 would be 0132 in hexadecimal, which would be safe. Thankfully, max HP increased in increments of 20, so only two such max HP values (770 and 2050; 0302 and 0802 in hexadecimal respectively) were possible to achieve without the -1 penalty to max HP from each direct use of Dark Chips (which were far inferior to using them for Chaos Soul Unison anyways), and both required you to have an odd number of HP+ 50s equipped.
 * In Phantasy Star IV, after the fight with Zio, two of your party members leave the group to pursue other things. This frees up enough space for the next two to join up. However, the fight with Zio can be extremely difficult, and the two characters who leave are the ones with the most HP and highest defense (assuming you didn't just equip Rune with two shields), meaning there is a very decent chance that Chaz, Rika, and Rune will all be Near Death when the fight ends. After the cutscene where Gryz and Demi leave, up pops a "Chaz was defeated!" message on the worldmap, and the game ends.
 * Also in Phantasy Star IV, there is the legendary "Level 99" glitch, which makes it so that leveling any character to 99 will actually make them lose skills. While this is true, the actual glitch starts activating around level 96 or so, with characters like Rika suddenly losing hundreds of technique points, and Wren losing the Positron Bolt skill (it still appears in the menu, but has zero uses available). The androids even start gaining a Mental stat (which, being machines, they normally do not), and Demi gains an impressive number of technique points (but no techniques to use them with.)
 * The first Baldur's Gate has the now infamous Beregost Bug, which comes in two frustrating flavors:
 * First, if you do a full save in Beregost (quicksaves and autosaves are fine), it is possible that your file will become corrupted. Thankfully, there's an application that can undo this.
 * The second, and arguably more frustrating of the two, is that, after leaving Beregost for the first time, it is possible that from then on, re-entering Beregost in any way, including the console, will cause the game to immediatly crash. Again, there's a workaround to this, but it requires a little bit more effort than the first one.
 * Mass Effect was rumored to have been tested on one kind of video card and one kind of sound card since it was a port to the PC from the Xbox 360. The result was a buggy crashy mess that generated tons of complaints and took months to fix through a combination of game and driver patches. Examples include:
 * The background music on the Citadel devolving into a medley of snapping, crackling, hissing and popping.
 * use of Biotic powers would toss the main character through the wall and out into the empty void surrounding the rendered game area. With the character trapped in the throw animation there was no way to recover or reload and the game had to be force quit.
 * The game would crash to desktop after completing a cutscene. These were unskippable and could easily be several minutes long.
 * The game would freeze during romance dialogues depending on what button on the keyboard was bound to "Talk".
 * During the  if you have been hit by a biotic power and are currently in the glowy blue ragdoll state while one of the mid-battle cutscenes goes off you are trapped when the cutscene ends. You can't enter the menu, and you can't move. The only way to get out is to restart the game.
 * Biotics in general are incredibly buggy. It's not only possible but nigh inevitable that at some point, if Shepard or one of your squadmates uses biotics on enemies in enclosed spaces (such as the bunkers or mines that make up about 75% of sidequests), the enemies will end up clipping through a wall, where it is impossible to reach them, either by shooting them or through the use of powers. The only way to progress in many places is to use Singularity on them (which will slowly whittle their health down; this is only available if Shepard is an Adept or Liara is in the party) or to exit the map and re-enter, which isn't always possible or convenient. If neither options are available, have fun reloading from the previous save, which was probably a long time ago.
 * Mass Effect 2 would at times send the party floating above the map on the other side of the Invisible Wall that surrounded normally accessible areas. In effect, you could walk freely where you were not meant to, but there was no way to get back and progress the game, save from performing a biotic charge on a ground bound enemy -- if you were not a vanguard or there were no enemies around, you could only reload a save.
 * A vanguard who likes to charge a lot will end up in a lot of buggy situations. There's many occasions where a charge at an enemy will take Shepard past an event trigger (where a cutscene is supposed to begin), only fixable by reloading from a previous save.
 * There's also strange glitches related to reloading several times in quick succession, where you reload the game only to find the enemies have simply disappeared. This can be good in some cases (allowing you to bypass difficult fights!) but in cases where you need to kill a certain number of enemies to progress, you'll be stuck until you reload.
 * Dragon Age II has a "stat-leak" bug: if Sebastian and/or Isabela are removed from the party without going through the party organization screen, their Friendship bonuses (+5% damage resistance and attack speed, respectively) are removed from your base score.
 * There's also a bug that can make Isabella Lost Forever. While doing her quest, after you kill the guys that try to ambush you, she'll tell you to loot a guy and find a key. It's quite possible to loot the key before she tells you to, and so the game acts as if you don't have it. Without the key, you can't enter the Chantry and finish her quest; the doors just don't react with you no matter what you try. Saved it after looting the key and don't have a backup? Too bad, you just lost your Rogue. It's still very possible to complete the game without her, so it doesn't become unwinnable, but you miss out on a strong party member.
 * Patch 1.04 seems to have introduced more bugs than it fixed...most notably endless load screens that freeze the game during Sebastian's personal quests ("Repentance" and "Faith"). Nice job breaking it, BioWare....
 * There are quite a few bugs in Lufia 2 Rise of the Sinistrals, both in Japan and in the U.S. The most complicated one is the Submarine Shrine, where a graphics screw-up makes the inside of the shrine almost completely black; however, you can still go up until you stop at, but you just won't see it OR . Thankfully, this glitch is fixed along with all the other glitches in the Europe/Australia PAL region version.
 * Fatal Labyrinth, one of the earlier titles on the Sega Genesis, requires you to venture to the top of a tower with randomly generated floors. To move up to the next floor, you have to search the current floor for the staircase that leads you there. However, because of the randomly generated (and shitty) nature of the game, sometimes it will forget to spawn a staircase. Search the floor all you want. It’s just plain not there, sometimes. Nothing can be done now but to hit the reset button.
 * Dungeons of Dredmor is a fairly buggy game, but usually it's something minor like stats not applying or the Player Character accidentally eating their own belt. But when Wand Lore was overhauled so you could craft your own magic wands, the tool you needed would crash the game most of the time. At least you got an achievement for it!
 * The Game Boy Advance port of Phantasy Star Collection is hampered by a bug that will cause everything but the music to freeze after a very short period of play - sometimes, as quick as 15 seconds. It's possible to very slowly make progress in the game by saving frequently (like every minute or so) and hoping it didn't freeze during the save this time, but even in the best case scenario, the game will freeze about 3 minutes after starting every time. While saving that frequently could theoretically allow someone to beat the games, it'd take the patience of a bodhisattva.

Shoot Em Ups

 * The Prismriver sisters' glitch in Perfect Cherry Blossom. Occasionally at the end of the girls' final spellcard, Merlin (the white-haired trumpet player) will fail to transition properly into it and continue to attack the player -- causing her to lose lives even after the battle has ended. Amusingly, Fanon gleefully turned Merlin into a nutcase after discovering the bug, and in doing so made "Merupo" the most recognizable of the sisters.
 * Also the One-Billion-Bug from Undefined Fantastic Object, that would crash the game if you reach one billion points. Thankfully, ZUN released a patch for it.
 * Scene 12-6 in Double Spoiler has a tendency to glitch and kill the player for absolutely no reason whatsoever. This isn't Hitbox Dissonance, this is the player just randomly getting killed by thin air. This can even affect successful clear replays. And this one has not been patched. Seen here.
 * Sigma Star Saga has the Forgotten Planet bug. Normally, when you are pulled into a battle, you must shoot down a certain number of enemies to win and continue the main story, and the stage will loop until you do. But killing a "tombstone" enemy occasionally bypasses the "end battle" trigger, meaning the stage will endlessly loop but no new enemies will spawn, making it Unwinnable. The "endless loop" bug was also present in the Forgotten Planet's boss level. Word of advice: don't level up during it.
 * Star Fox 64 has a very rare heartbreaker; after beating Star Wolf on Hard Venom (the last level of the game), Fox decides to go it alone from here. The CPU will control Fox's ship to the tunnel that leads to Andross. Problem is, if you're at exactly the wrong distance or angle away from the tunnel, the ship will just keep calmly circling around the tunnel and never get any closer. Video here. Round and round we go!
 * Gradius Gaiden's 7th stage, a volcano stage that gets sucked into a black hole, slows down horribly on a PS2. Hope you have a PS1 lying around somewhere...
 * The Commodore64 port of R-Type has a bug that makes the first boss unbeatable.

Simulation Game

 * Star Wars: The Gungan Frontier, an otherwise extremely fun ecosystem game, had a glitch where creatures that were paralyzed by an in game item would occasionally grow in size. The creature itself would stay the same size, but its graphic would expand. If the player did not notice this (which was very easy) and let the creature continue this way, the graphic would eventually fill up a large portion of the map and continue to grow, causing the player to have to either exit the game, or trudge through oversized pixels to find the exact spot that the creature was standing, and use a capture tool to remove it from the map, removing the graphic. It even occasionally happened to creatures who weren't paralyzed, though in this case, it was easy to notice a creature who was suddenly frozen for no reason.
 * In a series known for glitches and bugs of various levels of usefulness and/or annoyance, the original PAL version of Harvest Moon: Back To Nature takes the cake: Once your character gets married, and your bride asked you what she should call you from now on, every choice resulted in the game simply blacking out. You could reload and replay from that point, but getting further was impossible.
 * A lesser, but similar glitch (since fixed) occurred in Harvest Moon DS, where errors in the way the game kept certain stats and missing unbuyable items made it impossible to unlock the Harvest Goddess or Witch Princess as eligible brides. The game may also randomly freeze and the save file randomly corrupt. The fixed version still suffers from the occasional, but rare, freezing.
 * In Harvest Moon: Tree Of Tranquility, the player cannot marry Calvin due to a glitch (fixed in newer copies of the game) that freezes the game for the five-heart event, which the player must complete before marrying him. The company recommends "not getting his heart level too high" if you want to go into the mine (as that's where his event takes place). If you are a male or already married, there is no longer a problem.
 * The Japanese version of Animal Parade had a rather nasty glitch where recieving a present from someone over the WiiConnect service could completely remove all festivals from the calendar, making it so you could never go to one of them again. The English version outright doesn't have the WiiConnect feature enabled, to stop the bug.
 * Animal Parade has another nasty one in the "Missing Children" glitch, where certain circumstances can make your children disappear completely except for certain events, with "None area name" showing up as their location if you track them. This guide has more information about the bug.
 * The Sims 2 and its expansions tend to be buggy. Most of them aren't game-breakers, but then you get the things like object-corrupting RC cars, self-deleting portals whenever a player character juggles something, and repeatedly spawning NPCs. To EA's credit, they did fix that latter one quickly, but the modders got to it first. MATY & Simbology > EAxis. Also, there are multitudes of reasons not to abuse the game's cheat codes.
 * There also a black hole glitch in the Double Deluxe edition (at least). For some reason if you save after building a house, it and the land it was on will suddenly disappear. The lot is effectively gone, and there's really nothing you can do to recover the lot shy of resetting the map somehow.
 * And in The Sims 3: Late Night, several windows in the unpatched game will actually freeze up your game if you select them. A few debug objects will freeze the game also.
 * In The Sims 3: World Adventures, it is highly recommended that one make a backup of their save file before going on a vacation since returning back to your neighborhood has been known to do things like make your Sim be married or be the parent to some random Townies or just outright corrupting the entire save file. And who could forget, in the early patches at least, Blue Lot Syndrome?
 * The Sims 3 is generally like this whenever a new EP is released. EA will usually release a patch within a few weeks to combat the problem . . . but then said patch usually causes 5 more problems to spring up in its place. It's like an endless wack-a-mole game for the programmers and makes one wonder if they actually bothered to test these expansions properly before releasing them to the public.
 * Animal Crossing, of all games, has some in its handheld incarnation. Most notable is a glitch that would make the game freeze upon visiting an animal's birthday party, forcing a reset and an earful from Resetti. While this particular glitch may not show up for years, once it starts happening it's impossible to STOP it happening, meaning that you can never visit one of these parties again.
 * Also from the handheld version, one can obtain broken items that, if dropped, can never be picked back up, can create buildings, change the terrain, or prevent the game from loading past the title screen. Needless to say, certain people take great pride in deliberately sabotaging peoples' games through the Internet. Although only people on your friend list could enter your town via friend codes (the games don't allow towns to be visited by anyone not on your list), you had no way of telling if someone was nice or a griefer until it's either too late or you watched them like a hawk.
 * Black And White 2 was impossible to even start playing if you didn't have a mouse that had a scroll wheel, and was made by either Microsoft or Logitech. The initial release of the game wouldn't let you skip the tutorial, which at one point requires you to use your mouse's scroll wheel to zoom in or out to continue. That's right - they didn't test the game on any laptops or PCs with older/cheaper mice. Moreover, the box gives you no indication that you need a scroll-wheel mouse in the "System Requirements" section. They finally "fixed" it in the first patch by letting you skip the tutorial...but it penalized you for doing so, which caused people to wonder just whether the developers were in cahoots with Microsoft and/or Logitech to sell more of their mice.
 * Wouldn't surprise me if Lionhead really was back then. Lionhead these days pretty much exclusively works for Microsoft (either the Xbox platform or Windows). As for their Logitech connection: both Black and White and Black and White 2 had bonus quests and additional dialogue if you owned a Logitech iFeel Mouseman, a mouse with Force Feedback technology.
 * In Trauma Center, Mature Kyriaki gets upset if the first slice is sutured too quickly, and basically "says" Fuck this I'm going home. And then it fails to spawn, making the operation unwinnable.
 * The original Creatures had "Sudden Import Death Syndrome", which is exactly what it sounds like: occasionally, for no apparent reason, a creature would simply die on import.
 * Creatures 2, perhaps due to its rushed release, was full of bugs both minor and game-crashing. "One Hour Stupidity Syndrome", caused by a problem with the orignal genome (the simulation itself was working exactly as it was supposed to,) was especially infamous for making afflicted Norns essentially unable to survive after a while as they'd refuse to eat or sleep.

Sports Game

 * There was a design oversight in MVP Baseball 2004 that made it abnormally rare for left-handed hitters to hit home runs. This could be compensated for by jacking up the slider setting that controlled power, but that would result in righty batters hitting an unrealistically high amount of homers. The PC version received a patch that mitigated this somewhat; console owners had to make do until MVP Baseball 2005 was released.
 * The Commodore Amiga football game Kick Off 96 suffered from an infamous bug whereby first half injury time would continue indefinitely, making each match unfinishable. The game received the lowest mark in Amiga Power's history, with Stuart Campbell awarding it 1% in the magazine's final issue.
 * NFL Head Coach 09 suffered from a bizarre bug: If you saved the game between Tuesday and Saturday evening (in-game, not in real life), then any Free Agents you tried to sign on that save game would demand ungodly amounts of money, totally out of proportion with their real worth. In other words, the glitch makes the game more realistic.
 * If you have a computer that has just enough capabilities to run Pro Evolution Soccer 2010, expect to go through some wild framerate swings. At some points, the game will slow down enough that, next thing you know, it will speed up just enough for you not to see where you're leading the ball and end up losing it. This may even happen when you manage to get through the defense - the game may freeze for a split second and, when you take notice, the goalkeeper has already fetched the ball from your player's feet.
 * NCAA Football 11 received a doozy of a glitch after a patch: if a quarterback pump-faked backwards (towards his own endzone), every single player on the defense would abandon their coverage assignments and charge him, leaving all wide receivers open deep.
 * NCAA Football 12 includes showstopping bugs in Online Dynasty mode whereby the game can sometimes override a user game's score with a simmed game, resulting in a loss where there once was a win. It can even create a game out of whole cloth, showing a loss for a user on a bye week. This in a sport where even a single loss can cost you a National Championship bid. Then there is the possibility that the game might refuse to advance the week at all, a Game Breaking Bug which affects all twelve players in the league.
 * Tony Hawks Pro Skater 4 for the PS 1 is notorious for its lack of error testing, and graphically clips quite often. There are moments where you can grind a rail and suddenly it disappears and you fall THROUGH it and lose your combo. The worst part about this is that it's random, though can happen quite a lot in the opening "College" level.
 * Tony Hawks Underground 2 had a horrible tendency to freeze up completely at random while saving. There was no way of knowing if it would happen or not, and because it would freeze up while saving, all save data for that file would become corrupted. The only way to play that game to the end effectively would be to keep two saves, updating both, and hoping you could redo any challenge if the game froze up on your first save.
 * Several games in the FIFA series, from the introduction of friendlies in manager mode, until FIFA 12, had the Danish league bug, which simply was that the game skipped a season after playing one, if you managed a Danish league team

Stealth Based Game

 * An enemy in a certain room in Beyond Good and Evil drops a key when it's defeated. However, depending on how you defeat the enemy, the key it holds can spawn in weird places--such as in corners, or in the ceiling, or even slightly beneath the floor. Since you need the key to progress through the dungeon, the game becomes Unwinnable--luckily, it's fairly easy to reload from an earlier save if this happens.
 * It's also possible in a few places to "lose" your partner permanently. Not only does this keep you from finishing the game in the usual way (You lose access to their abilities, which you need to finish the game), it also prevents you from using your hovercraft, since you'll wait around for them to return before you can set off. Resetting is once again the only option.
 * If, for whatever reason, you decide randomly to backtrack to the Comm Tower from the Snowfield in Metal Gear Solid and ride the elevator down, and then save your game, the elevator will never come back again.

Survival Horror

 * In Silent Hill Homecoming, during the fight with, there is a quick-time event at the half-way point that must be completed into to face the boss's next form. Many have had problems with this event, as no matter how well-pressed the buttons are, some copies of the game just to refuse to register it, making the fight Unwinnable.
 * Another glitch is that on the Xbox 360 version in the hotel level, when you are on the highest reachable floor, there's one room with a hole to jump down into similar to one earlier that you climb out of. This room is crucial, as it contains the last post card needed to take back to the creepy woman. the glitch is that, the first time you walk up to the hole, it gives you the prompt to climb down. If the player doesn't take this command prompt and instead goes to continue exploring, when they come back to the hole the command prompt will not appear; there is nothing that can be done other than reloading your last save (Unless of course, you saved after you made the glitch without realizing it. then you have to restart the game). This is very troublesome, especially if you haven't saved in a long while.
 * In Clock Tower The First Fear, one possible way to escape from Scissorman among others is to run into the garage and either hide in the car or climb up the ladder and onto the above shelves. The latter, however, is incredibly unpredictable. If it does work, Scissorman would walk off, and usually when it works, it can be done by simply making Jennifer hug the ladder or stay up on the shelf without doing anything else to the ladder. If it doesn't, Scissorman will climb up the ladder and come after Jennifer, cornering her into a wall to kill her, the solution of which is to kick the ladder down. Unfortunately, since Jennifer has the incredible jumping skills of lemmings leaping from a pixel-high ledge, she can't leap down and traps herself on the shelves while Scissorman eventually crashes down to her from above and corner her until he kills her. The bug, however, is that, either by him climbing to her or her trapping herself there, a glitch can happen where the game has temporarily forgotten there was a wall at the far left corner of the shelf, so Jennifer will walk all the way to the left backwards until she walks off the screen, and Scissorman will follow her off-screen as well where she won't die but you can't do anything more than reset.
 * There's a bug like this in System Shock 2, where, near the end of the game, you're required to The only problem is, you need a resonator in order to take down the shuttles' shields; you can purchase one from a replicator nearby, but the problem is that a lot of people have recorded hacking the replicator at the 'wrong time' only to be completely unable to purchase the resonator. This makes it impossible to progress, as you need that resonator to proceed with the rest of the story. Thankfully, there is a cheat code that can summon the resonator and ameliorate things somewhat.
 * In Resident Evil Outbreak, occasionally a player using Alyssa's ad-libs during the very first scenario would cause the game to hang. Thankfully averted when an AI-controlled Alyssa use them...which is all the time.

Third Person Shooter

 * The Dreamcast version of Fur Fighters was rather buggy. One of the worst occurred in the level "The Bad Place." There's a bridge you have to cross, but once you pass a certain point, the character walks directly into the abyss for no apparent reason, sending you back to your last checkpoint. Apparently, if you cross at JUST the right angle, the character will stop walking before they reach the edge and you'll be unable to continue.
 * The PC port of Gears of War had a rather nasty bug that deleted your saved game. There is no way to back up these saved games, either. It was finally fixed with patch 1.2...which came out six months after release.
 * The Gamecube version of True Crime: Streets of LA had several hives' worth of bugs. The worst was one that would corrupt your memory card; essentially, it would wipe ALL your saves, and make it impossible to save anything ELSE on the same card.
 * In Star Wars Battlefront II, you can randomly fall through the ground. It's rare, and you can respawn, but you lose a soldier/reinforcement point on your side every time you respawn. Granted, it doesn't really break the game, but it's supremely annoying.
 * A particularly annoying one pops up on occasion when using Han Solo, if you have the points for or have permanently unlocked the precision pistol: you switch from his pistol to his repair gear, and cannot switch back. This leaves you with no damage-dealing capacity beyond five remote-detonate bombs until you die.
 * S4 League has a bug in its Chaser mode that renders the player without a HUD, making it very difficult to aim and leaving the player with no way to tell how much health they have left. Another form of this bug is even worse as it locks the camera in place, making the round virtually unplayable.
 * In Jedi Academy, there's one mission that has you going into a Jedi tomb to stop the Cultist bad guys stealing Force energy from it. To finish the level, you need to seal the tomb, preventing the Cultists from getting to it again. The entire level is composed of your typical railingless walkways over infinite drops, so the most efficient way to kill enemy Dark Jedi is to Force Grip them and quickly chuck them over the side before they Force Push back at you. However, if you employ this method on the last one (the guy guarding the tomb itself), instead of killing him directly, then the final objective - telling you that you need to seal the tomb - never triggers. It's not quite a game-breaker, since you only need to complete 80% of the levels to advance the plot, but it definitely breaks that level (right at the very end, literally two button presses from finishing).
 * The PC version of the 1999 Acclaim title Shadow Man is unwinnable on computers running Windows 7. For unknown reasons, various bugs pop up in the game when run under Windows 7, likely due to incompatibilities between game and OS and not even compatibility mode will fix these problems. The player will slide on any angled surface as if they were ice, lighting effects are broken to the point that the flashlight barely works and cutscenes don't always play properly. None of these make the game unwinnable. The game breaking bug takes place in the prison level as the zombie monsters can not be killed. They will fall to the floor when taken enough damage but the shadow gun will not finish them off and all other weapons fail to deliver the death blow, causing them to get back up. In some rooms, the zombies are so heavy that their gun shots will kill the player in seconds, rendering the game unbeatable as it will be impossible to get through these areas.
 * Ghostbusters the Video Game for both the 360 and the PlayStation 3 had glitch(es) that made two of the multiplayer achievements/trophies impossible to get. It was finally patched, 18 months later! And the real kicker is the patch only worked if the player hadn't already met the requirements for the achievements/trophies. Which meant practically everyone was screwed. And did I mention it's not possible to delete games in which you already have achievements in?

Turn Based Strategy

 * In Master of Monsters: Disciples of Gaia, if your Master reaches level 99, they can't go any higher. Why? Because if they gain a level at that point, the game will crash.
 * X-COM: Terror from the Deep has the Research Tree bug, where researching something too early can accidentally block off advancement in that research path. Most crippling is the Live Deep One bug. If you research a Live Deep One before you research the prerequisites for the Ion Armor, you won't be able to research the ships needed to complete the game. Thankfully, most of these have been patched away by the Windows 95 version.
 * Fire Emblem the Sacred Stones had a frustrating one that involved Wyvern Knights' ability Pierce (introduced in the NTSC version), which completely ignored enemy defense when it activated. Sounds great, right? Sure, except that when it activated while the unit was using a ranged weapon (Javelin, Spear, etc.), the animation would cause the game to freeze, forcing the player to restart the entire chapter. Thankfully, there was a way around this: the player could turn off the unit's animation (something most players are going to have done already by the time they have access to a Wyvern Knight).
 * Fire Emblem: Genealogy of Holy War has a nasty bug that can happen-- if Ethilin and Cuan live through the plot event where they're supposed to die, they'll attempt to take a nearby castle as a base. Unfortunately, you need to take that castle, and you can't take a castle from your allies, causing the game to become Unwinnable.
 * The American version of Rekka no Ken was just...buggy. Among the ways it can be crashed:
 * In the first chapter in which Kishuna appears, if an enemy unit is standing in the spot where he's supposed to appear when he does so, it will sometimes have its sprite changed to look just like Eliwood's. Attempting to attack this fake Eliwood crashes the game.
 * If a unit equipped with the Devil Axe attacks and ends up doing damage to itself, but is not killed by their own attack, and is then counterattacked, the opposing attack will instead make the unit's HP skyrocket to infinity and the battle to never end.
 * Not quite game breaking, but close: the enemy control glitch can occasionally lead to odd graphical errors where the terrain starts sliding across the screen. Moving the cursor will at least briefly make part of the correct map visible before it starts sliding, though other parts will still appear as something other than what they are. Since the unit movement functions as normal, this can lead to non-Berserker land-based units appearing to move over the normally impassable "Peak" terrain, as the Peak actually came from a different part of the map.
 * In its initial release, Civilization V suffers from a bad memory leak in which it's possible to never finish a very long game with many players. The game runs in 32-bit mode, which on 64-bit systems, limit the game's actual memory usage up to 2GB. Once the game hits 2GB, it will crash.
 * It's possible for Galactic Civilizations 2 to glitch in such a way that when you start the game, your ships become sublimely convinced that every single location on the map, including your homeworld, is outside the area they can move to. Being completely unable to colonise new worlds means that a game about building empires prevents you from building an empire.
 * In Super Robot Wars Destiny, a programming error makes it so that Super Robot-types end up raising their armor stats by 50 points, making it so that, when they reach max level, their armor is still pathetic. This makes machines such as Mazinger Z, Great Mazinger, UFO Robo Grendizer and The Big O weaker than they should be, makes God Mars a liability (as it causes a Nonstandard Game Over should it blow up) and puts Real Robots like Zeta Gundam and the (Proto) Garland of Megazone 23 into Game Breakers due to the fact that they have amazing dodging ability

Wide Open Sandbox
""Hostage dead, mission failed, support character gets sarcastic, broken game gets to fuck off"."
 * In Dwarf Fortress, cats will adopt dwarves without those dwarves needing to do anything. If cats which have been adopted by dwarves are slaughtered, the dwarf will have a tantrum. Tantruming dwarves can do bad things - so you want to avoid that. However, once the population of cats reaches a critical level (which is quite fast, because cats are promiscuous and have large litters of kittens) it becomes impossible to curb and keeping track of so many moving creatures causes the game's framerate to spiral downward rapidly into unplayability. This is known as a "catsplosion".
 * In the new version, creatures made of inorganic materials (such as Bronze Colossi) are Nigh Invulnerable. They can be destroyed by being melted into a puddle, encased in ice, or sometimes torn to shreds, but ordinary combat generally goes nowhere against them.
 * Some Hidden Fun Stuff is literally unkillable, since they don't have organs to damage. Though given that this is Hidden Fun Stuff, it's probably intended as a feature.
 * A recently fixed bug caused rain to melt creatures caught in it, including dwarves.
 * In older versions, if you happen to be on an evil-aligned map containing a stream with carp in it, you are doomed. Carp are already godless killing machines due to a bug in the skill system that caused them to get stronger by swimming and an overpowered bite attack. And undead creatures, which randomly appear in evil areas, are amphibious. The resulting zombie carp can not only maul anyone who gets close to the river, but follow the survivors back and murder them in their beds.
 * In Grand Theft Auto III, there are two generic black street gangs in one area. Over the course of the game, you can fully eliminate one of them. Starting a new game from the options while playing a game with that gang eliminated will also remove them from the new game, making that branch of missions Unwinnable.
 * Saving the game at the ice cream factory in Vice City has been known to corrupt many a gamer's save file.
 * In fact, using cheat codes in some games in the series will cause some hidden packages to disappear, making it impossible to get One Hundred Percent Completion. This is done intentionally, but it would have been nice to have some in-game warning first.
 * The Malibu crash (for lack of a better name), exclusive to the PC version (and possibly the PlayStation 2 version as well) of Grand Theft Auto Vice City, causes the game to immediately crash when nearing the vicinity of the Malibu. It's not known what causes it, but it causes the game to crash, saying "Error reading the Grand Theft Auto Vice City DVD."
 * The infamous Mad Dogg glitch in GTA: San Andreas. A glitch in a mission where you had to save him from his own suicide attempt by positioning a truck full of hay under him before he could jump off a building would become Unwinnable because he would jump off the building before the cutscene ended. This glitch also made the ‘’game’’ Unwinnable, and this is compounded by the fact that no one is certain what triggers this glitch; it seems to be completely random. Many suggestions have been made, the most commonly accepted "cause" being that it's caused by cheating extremely often, or using common cheats. This is discredited, since many people who never cheated once the entire game still had the glitch occur, while some that cheated extensively never saw it. One cause is the "pedestrians riot" cheat (which cannot be turned off), causing everyone to become hostile to each other. This mission is affected because Madd Dog's character attempts to run to the nearest NPC to fight them, and in doing so, runs off the roof and dies. This is made even worse by it being one of the last missions in the game, meaning that if you get this glitch, you're screwed and have to start all over and pray you don't get the glitch again. Though, mercifully, it seems as though it never happens in two new games in a row.
 * Also, if you attempt to play basketball in Madd Dogg's mansion, all basketballs on the world map will be deleted from the game, meaning you can't play it again in that particular save. This one is minor, since basketball is not needed for Hundred-Percent Completion, but another glitch involving the mansion that you should worry about involves saving there, which corrupts your file.
 * If you can manage to push a locomotive into your airplane hangar, the game will freeze after the doors close (which resets all the vehicles in the hangar) because the program won't know what to do with it.
 * Another glitch occurs when you have to steal a van with stereo equipment but you need to impress the girl behind it with your dance moves before she lets you get inside. Playing on an HDTV causes input lag, which means your button presses during the dance sequence are either out of sync or never registers at all, causing the mission and the game to become Unwinnable. To be fair, the game was released at a time when HDTV technology was new and developers weren't fully working on HD tech yet.
 * On lower-end systems that are well within the demands on the back of the box, the PC version of GTA 4 occasionally fails to load surfaces and objects. At speed, you can slam into concrete barriers that simply didn't appear until you hit them. It's also possible to go down a ramp into nothing because the walls, floor, and ceiling failed to load. Also, doing anything to the music (such as changing radio station, skipping a track on the user track player, the user track player simply loading another track) can cause a short section of music to repeat endlessly, with the game crashing shortly afterwards. You have a good minute of knowing that no matter what you do, your progress since the last save is gone.
 * Also in GTA4 it was entirely possible to end up under the game map, especially in the western harbor part of Algonquin island. People would not see you, but you could see them. And shoot them. It required a jump in the water and swimming/hugging a part of the docks at the right angle, if you get lucky and the waves hit a low spot, you are phased through the walls.
 * Bully: Scholarship Edition for the Xbox 360 added a music class that plays like a two-button rhythm game. Most of the time it's okay, but there's a bug that prevents double notes from registering roughly 50% of the time. This is particularly controller-snapping on the double note-heavy Music 3 level, essentially turning it into a Luck-Based Mission. Ironically, the less double note-heavy Music 4 and 5 are easier because of this.
 * Another glitch in the game, while not game breaking per se, it completely ANNOYING. After finding all 75 rubberbands for the rubberband ball, the game is prone to breaking and [even though you still have it in your inventory] the rubberband ball is inaccessable.
 * Yahtzee's Zero Punctuation review of Mercenaries 2 described a particularly crippling AI bug as follows: After failing a mission where he was supposed to rescue a hostage from the top of a tall building via helicopter, Yahtzee discovered upon retrying that the hostage now recognized him as soon as he came within earshot of the building and, in an effort to come and greet him, walked right off the edge of the roof and came plummeting down to his death several stories below.


 * More fun from Mercenaries 2: After March 17th, 2010, the game no longer plays if you have an internet connection, because EA has shut down all of its servers for Mercenaries 2. Instead of simply giving an error message, the game gets stuck "Connecting to EA server" forever and freezes up completely. Thanks, EA.
 * Spore has a really bad one in the space stage: if you invite allies to add ships to your fleet, they very commonly fly right behind your ship and get in the way of the cursor. If you fire a colony-spawning pack, and you accidentally click an allied ship, the pack fires horizontally into space, and you become trapped in the atmosphere of the planet, unable to save the game. This is very unfortunate, since the space phase is very engrossing, and the game has no auto-saving feature.
 * The most recent patch (1.05) added a couple more major ones. First, it screwed up the orientation of buildings placed over water/lava in adventures, rendering many unplayable. EAxis released a patch for the patch to solve that (1.05.1). However, the patched patch can still cause creatures to become almost completely un-animated, "sliding" around and maybe bobbing their head or wings a little, and this is only solvable by a reinstall. And this patch was supposed to improve creature animations...
 * If you attempt to skip either of the two migration cutscenes in said stage, your creature will be stuck in its egg and won't hatch. You're forced to go back to your last save and lose your progress.
 * Another one you might run into whilst playing an Adventure with the Galactic Adventures expansion is running into a building or static ornament too fast and getting stuck inside. Sometimes you can get out by trying to charge into a target, or using the sprint ability, but not everybody is going to have one of the two/you can't get out no matter how hard you try. Of course this means you'll hafta start the entire mission all over again.
 * Spore creates files in your documents folder for the things you create that you can copy and give to your friends. The common dangers of force-shutting-down your computer while a game is running become worse because of this. When reinstalling Spore, you HAVE to tell it to get rid of your old creations, because they are now corrupt and their presence prevents Spore from running. Imagine you had made hundreds of creations on that thing...
 * A few gamers complained that Planet Editor on Galactic Adventures crashed their computer. Completely. Every time they tried to use it.
 * It is possible for your starting nest in the creature stage (Where you first spawn), to appear wrongly, namely underwater. This in itself is not game-breaking, but the problem is that if you try to go on land, the [sea monster Border Patrol] comes and kills you, making the only way to progress be to search the coast in the hope that some creature is swimming.
 * The US release of Way of the Samurai 3 has an irritating bug with respect to the Records screen. Said screen is the only way to check what you have and have not done successfully. It's also where you see what you did to get the title you just got. One of the stats is Favourite Weapon. If it's a custom-made (forged) weapon, the game goes into an infinite loop, requiring the power button on the console to be pressed to turn it off. Fortunately, it doesn't cripple save data, and it can be fixed simply by starting a run, grabbing a randomly dropped sword, going to your house, pulling it out, leaving the console on overnight (unpaused), and then leaving Amana.
 * Alternatively, if you've used that forged sword for over 24 hours of game time, you may be better off starting a new game on the save file, discarding the sword, abusing the forging system to make a roughly-equal sword out of a random sword, and then leave Amana, as this will guarantee that the stat will default to another weapon.
 * Driver 2 and Driv3r are both full of these, due to being rushed for release.
 * In Minecraft, several of these can do anything from deleting your best items on death instead of dropping you, forcing you to start getting resources again from scratch, to getting you stuck on the (unescapable) bedrock roof of the Nether or dropping you out the bottom of the world.
 * Luckily, if you are stuck, you can set the game on Hard difficulty and let the hunger meter drain to empty and let the hunger kill you off.

Miscellaneous Games

 * Indie puzzle game "Chroma Shift" has two game-breaking bugs:
 * Playing with the mouse instead of the keyboard prevents the game from satisfying the condidions to unlock Lenore as a playable character.
 * High scores will refuse to save on some computers, and since the point of most puzzle games is to rack up a high score...
 * The Elite series of space trading games featured several bugs, due to the sheer size and scope of the series. The first wasn't that bad, but Frontier: Elite 2 had some nasty ones - your spaceship's autopilot would occasionally fly you through planets, sometimes without sustaining damage - and the third game, Frontier: First Encounters, was released in a semi-completed state. For example, the biggest, toughest, and most ultimate spaceship you could buy was basically useless, since firing any of the 'turrets' resulted in you hitting yourself; early releases of First Encounters would crash when you fired a laser, or tried to use a joystick connected to a SoundBlaster gameport, or played certain missions.
 * The ZX Spectrum version of the original Elite had a notorious one, caused by its copy-protection system, which consisted of a plastic lens. Anyway, the lens was used to view a distorted captcha on the screen to gain access to the game. Trouble was, the lenses from the original shipment were badly engineered, making it impossible to play the game at all.
 * Tricking the player is half the fun in Eternal Darkness. Most of the Game Breaking Bugs type are pretty obvious, but still entertaining: The Gamecube turning itself off, the game mistaking your request to save as a request to delete, and even the infamous blue screen of death!
 * Parodied in the fifth game of Strong Bad's Cool Game for Attactive People, which requires you to deliberately induce one of these (which is nigh-impossible without cheating, but the cheat is easy to activate) in a game-within-the-game.
 * Of all things, the Chess software that shipped with Apple's OS 10.4 had one of these. Set the computer to its hardest setting and make sure you're white. The correct way to break the AI was 1. e4 c5 2. Nf3 * twitch** freeze* as the computer forgets how to continue a Sicilian defense.
 * There was a similar bug in an early version of Mac OS (c. 1995 or so) that also came packaged with a generic Chess game. If you tried to lure the computer into a Fool's Mate the computer would not only ignore the checkmate, but would move twice before letting the game continue as normal.
 * It could be an urban legend but it is said that one of the early chess supercomputers was programmed to make the best move. Unfortunately this meant that where it could deliver mate in more than one way it would go into a loop to decide which was 'best' and lose on time.
 * Action 52 has games which have tons and tons of these bugs. Actually, it's more like a big bug with bits of games in it.
 * The most infamous one is the NES version of Ooze. Active Enterprises held a contest saying that the first person who could get past level 5 wins $104,000. Sadly, the game freezes near the end of level 3 making it impossible to win.
 * On the third level of Lollipops, the Glitch Gremlin invades the soundchip and permanently messes up the music.
 * Alfredo and Jigsaw completely fail to load most of the time, even on emulators.
 * One of the minigames in the first Rayman Raving Rabbids game has messed-up control recognition, so the game will incredibly rarely register your control inputs. This is very annoying as this is a Timed Mission, and you get a pretty cosmetic reward for One Hundred Percent Completion.
 * There's another minigame where, at least on the Wii version, you're required to find a hidden Rabbid using the sound coming out of your Wiimote's speaker. However, there's a bug that happens 9 times out of ten where all you'll hear coming out of the Wiimote's speaker is static.
 * Homeworld, at least in some reissues, features a killer. Sometimes your capital ship bay will just stop working while still accepting orders for new ships. The resources will be subtracted from your total but the ship just won't be delivered. Salvaging becomes impossible as well. This bug carries over into later missions and basically means starting again.
 * In Backyard Football 2006, if you throw the ball backward, the camera just zooms out...and zooms out...and zooms out without calling an incomplete pass. Then you have to start the season game all over again.
 * Yu-Gi-Oh Reverse of Arcadia has numerous bits of Copy Protection as it is, so this may in fact be one of the various parts of the Copy Protection activating, but occasionally (albeit exceedingly rarely), when a player takes damage that does not reduce their LP to 0 after being attacked directly 5 times in one turn, the attacking player will say their "duel victory" quote...and the defending player will spontaneously lose the duel, even if there is a chance for that player to win in the next turn.
 * The N64 game Battle Tanx has an infinite health cheat, but the game doesn't always let you turn it off. If you use the cheat during a bonus level, where the objective is to survive for as long as possible, you enter a situation where the bonus level will never end because you can't turn the cheat off.
 * ‘’Cooking Mama’’ has this if you use cheat systems. Normally, infinite time is great because it allows you to get very good every time unless you cock up in some other way. But if you are in a task where time is essential to winning (like seperating egg yolks) thus rendering you to get bronze, which ruins your chances of Hundred-Percent Completion.
 * Wonderland Adventures used to have a bug where you could use blink to teleport through a single wall tile. This "wallblinking" became famous after spots were found where you could blink in and then waste your blinks, leaving you stranded and making the game unwinnable. Perhaps nastier was The Void where you could skip the power cube levels by blinking past the gates at the cost of forfeiting One Hundred Percent Completion. Except there's no indication you can't go back to the void once you finish the final level. This bug was fixed in a later version, but since many people liked the shortcuts it provided, the more adventurous people can still try it out by enabling it with a cheat code.
 * Portal, of all games, has a rather weird one where, if you toss the Anger Sphere into the Incinerator just as your time runs out, you die from the neurotoxin as G La DOS sort of implodes. You're ejected from the center and treated to the brief surface cutscene as per normal, but the game hangs there. You don't get to see the ending, and you don't earn the Heartbreaker achievement. Quite a bummer if you think you've just barely managed to pull off a victory.
 * Oregon Trail 4th and 5th Edition have a lot of these, especially crashing bugs, as well as compatibility issues with Windows 2000 and XP.
 * In the old PC Point-And-Click adventure game Pink Panther: Hokus Pokus Pink skipping through the cutscene where the "Star's Bite" collection is unveiled makes the camera un aquireable, thus making the Greek Mythology chapter Unwinnable.
 * Monty Python's The Meaning of Life was released commercially, despite its developer going out of business. As such, the first two 'episodes' of the game (themed around life and the afterlife) are more or less flawless...the final section, which takes place entirely in Terry Gilliam's cottage, is quite troublesome. Primarily, the final task of the game is broken. After collecting a number of cheese wedges, the player is meant to build a ladder with the cheese in order to reach the trap door to the Attic and complete the game. Opening the trap door doesn't trigger the end sequence as it should, but rather, presents the player with a black screen. (A workaround does exist, involving usage of the 'Windows' keyboard key.)
 * In the defunct browser game Little Cave Hero, you'll often find arrow launchers in levels. If your computer runs the game with lag, it'll have the bizarre effect of increasing the arrows' speed. At "best" the arrows will wreck your score. At worst, levels will become Unwinnable (e.g., in the level Signs, you won't be able to break one fake wall because a arrow keeps stunning you before the breaking animation ends).

Others

 * A few from Dungeons and Dragons:
 * The Truenamer class from the splat book Tome of Magic is infamous for being broken in the sense that the class is unplayable as written. One noted ability of the Truenamer is that its abilities get weaker and harder to use as it levels up (You need to meet a check that goes up by 2 each level, while you can only put 1 more point in a skill a level), assuming you can even meet the DC required for an utterance at a low level (unlikely as due to another bad piece of writing the base is 15 vs the lowest level foe you can fight, while the normal first level is + 4 from skill ranks and a + 3 from ability score plus the result of 1d20, yes, your main ability is effectively luck based (need an 8 or higher, can't take ten) as to if it actually works against the least threatening foes.) and truenaming checks get harder to make as you attempt to do it more than once a day.
 * As with much of the late 3.5 game, this was possibly a prototype for fourth edition. In 4E, all of your attack rolls increase by 1/2 per level while all of the defenses for any NPC go up by 1 per level (directly compared to your Truenamer skill going up by 1 per level and the DC going up by 2 per level); 4E "solves" this problem by mandating you gain magical items and increase your ability scores to make up for the difference. It was probably expected that any Truenamer would pick up a magical item that grants + 15 to skill checks.
 * The Tome of Magic also neglects to include the target number for an entire class of Truenamer Utterances. The DCs were later set by errata.
 * Also in 3.5, it's possible to get a sorcerer with Wish as a spell-like ability with no GP or XP cost at level 17. This technically allows you to get free rings of three wishes.
 * The Drunken Master Prestige Class relies on getting drunk. The problem is the intended entry is Monk, which becomes immune to poison (And alchool is classed as a poison in the rules) at level 11, and Drunken Master does not include wordings that overwrite this. Therefore, it's possible to make it impossible to use your class features.
 * An Epic Destiny in 4th edition, the Archlich, was also broken: one of his class features (that whisks him away to his phylactery when he hits zero hp instead of going unconsious) made one of his other class features (stay alive and power up when killed...which happens after you get below zero hp) impossible to use. It was errataed later.
 * Yes-it-exists-and-the-world-is-stupider-for-it RPG Racial Holy War is not just unplayable for the reasons you'd expect something with that title to be; the combat rules don't work at all (modifiers are listed, but not the basic chance they modify, making it impossible to actually attack anything), and the outnumbering system (if a party is outnumbered by a given amount, they flee) doesn't take any account of what is outnumbering them, meaning the supposedly heroic white warriors might conceivably run screaming from a mob of babies and pensioners. There's some debate as to whether the game is a parody or just that dumb.
 * Amusingly enough, one of the Lord of the Rings RPGs had a similar issue; in army combat, there were modifiers based on the troop numbers, but they were based on the absolute difference, not the relative difference. So a thousand-man advantage might give an unbeatable bonus...meaning that 20,000 undead knights couldn't beat 21,000 hobbits with sticks.
 * On the Pyramid game show franchise (e.g. The $25,000 Pyramid), if both teams were tied, each team would play a extra round apiece with the subject of "Words that begin with the letter '?'". Several times, the teams would get the same amount of points in each round, and still be tied after the tie-breaker. This has led to episodes where teams would be playing four or six rounds more than the usual six to decide who would play in the Winner's Circle. Sometimes, however, the producers would fix this by having BOTH of the day's celebrities play for both the day's contestants at the end of the week (as opposed to one celebrity and one contestant). This was later fixed in the 1980s versions by changing it so that whichever team got its seven tiebreaker words faster won.
 * As written in the core book, there's no way to use skils in Rifts, because there's no way to resolve skill checks.
 * In the board game Hero Quest, it is entirely possible to lock the game into an unwinnable state by making either the Elf or the Wizard use the spell "Pass Through Rock" then passing through one of the many boulders that are used specifically to stop you from going to rooms to have no way in and nothing of interest thus trapping you on one side of the board with no way out.
 * "Empty" rooms in the board are considered to be solid rock. That being said, there are a couple of passages that close behind you in the game and which can be screwed by use of this spell.
 * In-universe example: Nanny Noah's Treasure Hunt game in The Lost Crown: A Ghost-Hunting Adventure can only be completed if you visit, but that building is closed on the day when it's supposedly being played by the local children. Fortunately, this doesn't stop Nigel from field-testing the hunt on the previous day, so it's only a Game Breaking Bug for NPCs within Saxton's Verse.
 * In an early edition of Warhammer 40000, the Tau had a unit called the Devilfish. Due to a loophole, since they were technically flying units, they couldn't be shot at by ground forces, but you couldn't shoot under them or through them because they were low to the ground and flanking rules. Players of the Tau would move two Devilfish into a V-shaped wedge, and then move troops into it, creating an assault-proof bunker. Worse, the troops inside the bunker could shoot at you if you tried to rush it, and even with armies that had decent anti-tank weapons or artillery, the tactic was difficult at best to beat. The rules were modified so that Devilfish were attackable again, as well as several other changes that have made the "Fish Of Fury," tactic to be a much reduced threat.
 * In most NES games, using a a game genie device and entering the code: "IKAAAE" corrupts important data in the cartridge, and as a result, the game becomes a total mess that's liable to crash.
 * Some results: Super Mario Bros is the best known example of this, here some others.
 * League of Legends had the Anivia stun bug. Normally she has the ability to shoot a ball of ice that damages and stuns enemies within range when it bursts. After one patch the range on this detonation became global, allowing her to spam that spell from anywhere (such as in the summoner fountain that restores mana at high speed) and hit the entire enemy team with it every few seconds. Obviously this made a match against Anivia essentially unplayable, and it was fixed very fast.
 * There was also a bug with Yorick's ult. Yorick's ult would summon a spectre of an allied hero that Yorick would control. However, if they died while the spectre was up, they would control the spectre for a little while. At launch? The person "resurrected" with Yorick's ult would die repeatedly.
 * There were a few instances where this happened in Legends of the Hidden Temple, specifically when they reached the temple itself and the game was rendered Unwinnable By Mistake. A few teams lost time because they couldn't open the door despite completing the obstacle. (Sometimes it didn't register a button press) However, one of the absolute worst cases was in "The war fan of the forty seven ronin", wherein a temple door closed and re-locked behind one contestant, who subsequently got ejected from the temple. Their partner came into the temple next, and was stopped by a door that their partner just passed through.

Non-game examples

 * In-unverse example presented in The World God Only Knows anime. During episode 4, the main character, Keima, is obsessed with trying to beat a Dating Sim game which is filled with bugs and glitches which causes a certain scene to replay over and over. Despite the game being very buggy and glitched, he vows to find a way to get out of that repeating scene bug via trying different options/selections. The game company released a lot of patches, but didn't fix everything, and eventually went bankrupt, so Keima feels that he's the only person left who can "save" her. He sort of manages to get past the repeating screen glitch, but then hilariously a bunch of random characters appear on the screen and the game freezes up. Despite that, he still vows to try to find a way to beat the game.
 * Homestuck has two. The first is prototyping a First Guardian, which will result in every enemy the heroes faces having First Guardian powers. And unfortunately, the most powerful enemy of all has no interest in following the rules of the game. The second is Lord English's
 * Powerpuff Girls has the Zelda clone that the mayor was playing in one episode. The mayor killed his fairy, which automatically treated him to a game over despite his character still having five hearts.
 * Having the cinematic rights to your game bought by Uwe Boll. He doesn't even have to make the film--it's going to be a disaster if he does, but his tying up the rights means no-one else can make a film of your franchise until the rights are wrested back away from him.
 * In Gintama, Gintoki and Kagura end up competing against Hijikata and Okita in a multiplayer virtual reality RPG to see who can clear a section of the game first. However, the game is a terribly glitchy beta version, and Gintoki starts off poisoned so he can't even walk to a shop to get an antidote without dying, and Hijikata starts with so little HP that he ends up killing himself by stubbing his toe on a sign accidentally. Predictably, their partners end up ditching them, and the two are forced to find loopholes in the RPG's mechanics to progress without them.