Throw It In/Video Games

"Nate: CAN'T YOU ASSHOLES SEE THE HELICOPTER?! I HAVE ENOUGH TROUBLE ALREADY!!"
 * Many Good Bad Bugs that were eventually worked into the final game as an Ascended Glitch.
 * The classic Space Invaders gradual speed-up of the invaders, as more are shot, was a Good Bad Bug resulting from the programmer pushing late 1970s hardware to its limit. It allowed the game to gradually get harder, creating the idea of difficulty curves.
 * One of the most famous examples of these are the "multiple coin blocks" in the original Super Mario Bros. Originally, these blocks which gave out numerous coins when hit started off as a glitch that was removed, but the developers liked it so much that they reprogrammed it back into the game as an actual feature.
 * The one Good Bad Bugs Throw It In example that's not Ascended Glitch but Shout-Out: I Wanna Be the Guy has a Good Bad Bug that makes it possible to skip Kraidgief's second phase before he rises up, which would also make the rest of the battle a total pushover since he would be at a much lower height and thus much easier to shoot. Word of God says it was kept in "since it works just like Kraid from Super Metroid".
 * When creating the character model for Tomb Raider's Lara Croft, creator Toby Gard was trying to make a minor adjustment to Lara's breast size. He selected all vertices in the breast to resize them, but the mouse slipped and they increased 150%. The team loved the new look and Lara's famous physique was born.
 * Somewhat similarly, the ridiculously long scarf worn by Hotsuma in the PlayStation 2 Shinobi is a result of a programmer gag: originally it was a normal-length one, but someone made it a lot longer, everyone liked it and they proceeded to make it even longer.
 * Knights of the Old Republic has an in-universe example, with HK-47's famous 'meatbags' catchphrase. Apparently soon after Revan built HK-47, the droid called Malak a 'meatbag' just because. Malak was really pissed, but Revan thought it was so funny that he reprogrammed HK-47 to call everybody a 'meatbag'. Although unintentional, the behavior was kept in.
 * Metal Gear Solid 3: Snake Eater - Ocelot's trademark hand gesture was an improv by the motion actor that made everyone laugh so hard it became the character's Catch Phrase - if a hand gesture could be a catch phrase.
 * Maybe to invoke this, Hideo Kojima had the Motion Capture actors for Naked Snake switched so that the one who specialised in action sequences did the dialogue scenes, and vice versa. In one scene EVA leans in to kiss Snake, and Snake's actor- unused to doing romantic scenes- instinctively edged away. They kept it in since the response was cute.
 * In fact, according to the Director's commentary, a lot of the things in Metal Gear Solid 3 were improvised and not actually in the original, initial script draft.
 * In a similar vein as above, the Honest John's Dealership character of Metal Gear Solid 4: Guns of the Patriots's pet Monkey was thrown in when they realized that Raiden's motion actor did a pretty good imitation of a Monkey. Insert your own "Raiden is the Butt Monkey" joke here. That, as well as the fact that Drebin seemed too bland by himself in Kojima's eyes.
 * Kirby as we all know him was only a placeholder character for Kirby's Dreamland. They ultimately went with the little blob.
 * Wii Sports was originally set up to be a Mario title. The test audience surprisingly preferred the Miis. Try not to think too hard about what boxing would have been like.
 * ...or if you really wanna know about Mario Boxing, play the DS version of Mario & Sonic at the Olympic Games. It had a boxing event which the Wii version lacked.
 * One of the levels of Portal can be finished in mere seconds, by using shortcuts to skip the entire level. When playtesters figured this out, the developers decided to keep it, since only advanced players would know how to utilize it. In fact, in the advanced versions of that chamber, the qualifications for gold medals require that you do this.
 * The commentary put it like this: If the exploit takes more skill to perform than doing it the intended way, it's perfectly reasonable to keep it in.
 * In a non-gameplay example, many of Raz's lines in Psychonauts were ad-libbed. They were so funny, the folks at Double Fine decided to keep them.
 * According to Dave Grossman Guybrush Threepwood's first name came when Monkey Island was in development. Since he had no name yet, his character art was simply named "Guy", and when Steve Purcell, the artist responsible for "Guy's" sprite, saved the file, he added "brush" to the end, to indicate that it was the Deluxe Paint brush for Guy, creating a file called "guybrush.bbm". They eventually just went with that, and had a great deal of fun commenting on his weird name.
 * According to Tim Schaefer, most of the dialogue in Secret of Monkey Island was thought by him and the other writer to be placeholder, and that the bigwigs were going to hire some "real" dialogue writers to do the actual stuff, but the humorous placeholder dialogue was so funny that they decided to leave it in. This actually had quite an impact on the gameplay itself and lead to the "rubber chicken with a pulley in the middle" bit.
 * The name of the god Armok from Dwarf Fortress was taken from a variable used in the game's predecessor Slaves to Armok: God of Blood standing for the number of available arms: arm ok.
 * Working on the upcoming necromancy update, Toady discovered that he could accidentally cause necromancers to raise disembodied skin creatures in addition to more conventional undead. He decided this made as much sense as the walking skeletons did, and published it in his development log as one of the new features.
 * Most of Kefka Palazzo's dialogue in Dissidia Final Fantasy was actually ad-libbed by his voice actor, Shigeru Chiba, and his tendency to change the tone of his voice mid-sentence was also due to Chiba.
 * Similarly, in Final Fantasy VI, the game that Kefka Palazzo originated from, his infamous introduction scene (barring the flashback) was not in the original script. Originally, he was intended to simply arrive at Figaro Castle and demand for Terra. However, Yoshinori Kitase felt that the scene was too boring to make completely normal, especially when they had only Amano's artwork of Kefka to work with, so he added in a scene where Kefka is complaining about Gestahl sending him off to Figaro, in the desert, on a reconaissance mission, and then stating that there is sand on his boots, causing the soldiers to wipe the sand off, and then, after laughing maniacally, berates them as idiots, with the intention of giving the implication that Kefka may be missing a screw or two from his head. They kept it in, and this also resulted in Kefka's characterization that we know him by to this day.
 * An in-universe example of this trope was also used. Ultros, feeling sore about his earlier defeat, decides to get his revenge by dropping a 4 ton anvil on top of Maria/Celes, but had a five minute delay due to his miscalculating the amount of strength and time he needs to actually attempt to push it onto Celes/Maria, giving Locke and the rest of the Returners (who discovered Ultros' plot due to a note in the dressing room for "Maria") enough time to halt his plan. Unfortunately, they also ended up interrupting the play by knocking out two key actors in the opera production (Draco and his rival suitor for Maria.), resulting in Locke and the returners improvising, with Locke trying to do his best (even if abysmal) attempt at mentioning that he'll take Celes's hand and not Draco or Ralse, and Ultros challenging Locke to a duel.
 * Demyx of Kingdom Hearts II was written as a Satellite Character, but his Japanese voice actor threw in lines and quirks that gave a little more character to him.
 * And the fans took it from there.
 * Before the production of Kingdom Hearts: Birth By Sleep, Sora's japanese Seiyuu jokingly whined about having to voice The Hero all the time and asked if Nomura couldn't give him a few more "evil" lines. And so, Nomura created
 * The famous Post 217 in a NeoGAF thread about Scribblenauts became popular enough for official artwork to be made of it. Soon after, the developers confirmed that "Post 217" was an object in the game's dictionary (it blows the map up).
 * Minecraft: Prior to patch 1.8, if you went an extremely-far distance in your Minecraft world (12,550,820 in-game meters, or roughly 820 hours of straight walking) you would run across a place called the Far Lands, where the terrain would suddenly become severely distorted and laggy due to a glitch in the way in-game worlds were generated. Originally, Notch said he liked the idea of a mysterious place so instead of fixing it, he kept it in. But in patch 1.8, he accidentally fixed whatever it was in the world generation process that created the trademark appearance of Far Lands. Currently, the world simply presents you with an invisible barrier, and Notch has not yet given any world on whether or not the Far Lands will return.
 * Creepers are the result of a failed pig model.
 * Warcraft 3: The Frozen Throne's Pandaren were originally an April Fool's joke that people responded to, so they were thrown into the game, with a side mission and a hero in the orc campaign. Blizzard even gave their race a tidy backstory and are a playable race in World of Warcraft: Mist of Pandaria.
 * In Quest for Glory IV, every evening in the Inn there are three villagers who convene. The voice actors had great fun ad-libbing lines for them, including a rant on how one of them used to be an elephant herder (the game is set in a country based rural medieval Romania, BTW, filled with forests and swamps) but the elephants all started dying out. The ad-libbing is quite apparent as on many occasions their speech do not even match what's written in the dialogue boxes. At one point the characters even speak out of order of what's being seen at the screen.
 * ... that's because the game is buggy.
 * The story passed around is that the diskette version (which had no voice) was finished before the CD edition, which had voice acting. The developer loved the ad libbing that the voice actors did so much that they were not only allowed to continue but were used in place of the conversations in the diskette version, which is why they don't match.
 * In the game Plumbers Don't Wear Ties, there is a scene where the male protagonist Narmfully flubs a line leading the crew members off screen to laugh about it. And they decide to leave it in anyway. The Angry Video Game Nerd points it out, although you may want to keep this link in mind.
 * In Grand Theft Auto III the pedestrians have a strange habit of jumping in front of the vehicle you're driving - this was originally a glitch in the AI that the developers found quite funny.
 * In a similar vein, in San Andreas on occasion planes would crash for no reason, a result of a less-than-airtight approach to random generation of flight paths that allowed the possibility of planes' trajectories intersecting with the ground. It was kept because it added to the hilariously crapsack nature of the game.
 * Many of Nathan Drake's one-liners in the first Uncharted are the result of voice actor Nolan North's improvisation while watching gameplay footage of his character.
 * Perhaps one of the more noticeable adlibs is on the Train level, when being chased by an attack helicopter and some more grunts show up:

"Alyx Vance: Well, Gordon... unless you have a better suggestion... He is a robot. He's done the math. Alyx Vance: [to Dog] You did do the math, right? [Dog sheepishly shakes his head]"
 * According to North, Charlie Cutter's claustrophobia in the third game was ad-libbed by his actor Graham McTavish, who thought it'd be funny as Charlie freaks out while making his way between a very narrow passage.
 * Much of the sidequest data from Septerra Core was this.
 * The Onyxia encounter in World of Warcraft was intended to have her Deep Breath ability used as a finisher on groups that had a significant number of players already dead. Due to a programming bug, it was used much more frequently, and was only left in because it didn't stop people from killing her.
 * Most of the swearing in Brutal Legend (especially on the part of Ozzy Osbourne's character) wasn't in the original script. But Tim Schafer decided to keep it because, well, it fits in.
 * In Undefined Fantastic Object, Minamitsu Murasa's stage theme contains a sudden pop, caused by a Windows notification while ZUN was recording it.
 * Apparently when Fawful's dialogue was being translated for the English release of Mario & Luigi: Superstar Saga, several translation errors were noticed but kept in the game anyway since Nintendo of America figured it would still be in character for someone like Fawful to say.
 * The 2009 Bionic Commando game features an Easter Egg where you can listen to one of Super Joe's flubbed lines: If you die on a certain boss in the game and try again, instead of telling Nathan to fight the boss, he tells him "You'll just have to fuck it".
 * Prior to the release of Pokémon Red and Green, one of the developers realized that, once he took the developer's tools out, there was room for one more mon. Since there were in-game references to the Pokémon Mew (where they got the material for Mewtwo), he decided to make it playable, but without a way to get it. No information was given about it, because except for the higher ups at Game Freak, no one knew you could get Mew. He figured they could give it away later, and a tradition was born.
 * Except for the Mew glitch, which allows you to get it normally by fooling the game into making it appear. This is due to the way the game handles numbers as code.
 * In Half-Life 2: Episode One, as Dog is about to throw a car containing you and Alyx across a pit to the, the following exchange takes place:


 * The head shaking was originally caused by a glitch and occurred randomly, but when it happened at just the right time in an early version of the game, the playtesters thought it was intentional, and the developers decided to make it a feature.
 * Interestingly, the gunships firing at the RPGs as opposed to the player was also originally a glitch, but they realized it added an extra challenge to the gunships and left it in (the glitch was caused by telling the gunship to attack the "most dangerous target", which the AI proceeded to assume was the rocket that could actually damage it, not the guy that had fired it).
 * A similar case during playtesting. At one point in Episode 2, you're gently prompted into throwing a grenade into a dumpster full of boxes. Do this the first time and the Fast Zombie hiding in there will toss it back out. It was originally a physics glitch caused by the boxes that would fly out when the Fast Zombie emerged, but like D0g's Indy Ploy, it was well received and left in.
 * The Crystal Theme from Final Fantasy. Quite possibly the most iconic song in the series. Put together by Nobuo Uematsu in ten minutes.
 * Samus Aran was originally going to be a guy, and is even referred to as male in the original instruction manual. Apparently, one of the developers thought it would be funny if the players found out she was female at the games end. Somebody agreed, and the rest is history
 * In Sam and Max Freelance Police: The Devil's Playhouse, one part in the script asked for some characters controlling the body of a giant Kaiju monster to make it do an "anime pose", intended as an homage to Voltron-type anime. The animator in charge of making the pose innocently asked the writer, "You mean like Power Rangers or like Sailor Moon?", to which the eavesdropping person in the neighboring cubicle immediately popped his head over the side and said "Oh my god, make him do 'Sailor Moon'". As a result, instead of doing a Voltron pose, the monster does a version of Sailor Moon's Transformation Sequence, which is a total non-sequitur but really, really funny.
 * Super Mario Bros. 2 was made exclusively for a Western release as a Dolled-Up Installment, but several elements from that game made their way into the Mario canon proper, such as Shy Guys, Bob-Ombs, Luigi being taller than Mario, and Peach's ability to float.
 * Phoenix Wright had this quite a bit in terms of the text. After the game's final script was made for the English version of the game, the port team had a reading of the script. During one of these readings of the Recipe for Turnabout script they got to the part in Blue Corps and they were reading the dialog for when someone presents irrelevant evidence. Original the scene was just meant to be Lisa Basil explaining that Blue Corps uses a "Super Administrative Restricted Desktop Access Password-protection system" before Maya said "That's madness!". When the staff read this part out, one of the writers jokingly shouted out: "No Maya. THIS. IS. SPARDA!". This got a massive laugh from the team and the script was edited to included the improvised joke.
 * During the development of BioShock (series), the developers were surprised to find that the telekinesis power allowed the player to move the anchor points of trip wires as if they were regular objects. The devs then decided to tweak that behavior and have it be an actual feature of the power.
 * Elzam's Leitmotif always being played when he's in combat was initially a programming bug (as he was a boss that switched to your side, and bosses always have their theme played). Since then, it seems both fans and developers loved it, making nothing able to override Trombe!.
 * There's actually a bit more to it than that: When he switches to your side, instead of changing his music's priority from "boss" to "player," they just added the "player" priority value to his already high "boss" value, causing his leitmotif to have higher priority than any other music in the game, including other bosses.
 * As it turns out, Link's upgrade to Bishonen status between Links Awakening and Ocarina of Time was the result of an offhand comment made by the wife of one of the developers.
 * Bulletstorm has a saturation of swear words (including modified swear words that sound like they came out of a maternity ward for schizophrenics) because the swearing was in English and the developers of the game were Polish, so they added in what they thought were regular muttering swears and got the unholy result. Seeing as how one half of the game is about making insulting, violent kills, this plethora of insulting, violent swearing ends up as the other half of the game.
 * The gauges screen in B-17 Bomber was originally meant to be a debugging tool to be removed in the final product but ultimately was left in because developers liked it so much.
 * In Fire Emblem it was common for advanced players to exploit the fact that units without weapons in their inventory can't counter attack to use the Jeigan as a wall/lure without killing enemies and "stealing" experience, to lure out recruitable characters who may get killed in a counter attack before they can be convinced to join and (rarely) to hold a chokepoint without killing enemies (since if an enemy dies to a counterattack another enemy can use their spot and attack for potentially lethal damage). This became an actual feature in the ninth game onward with the ability to unequip weapons.