Difficulty by Region

Games with various difficulty levels allow you to choose how hard or easy you want the game to be from the start. While some can be easy or hard no matter which one you pick, some games may seem harder or easier just because of the region the game was made in. Typically this occurred due to there being a belief in Japan that Americans preferred harder games; often US versions would have the lowest difficulty setting totally removed and / or an even harder bonus mode added. However, the inverse also occurred at times—some Japanese game developers felt that Americans (usually, but this could apply to PAL regions too) would not be able to handle a game's difficulty, so a North American release would be made significantly easier, or replaced entirely.

Another reason for higher difficulty in international versions is that renting games is illegal in Japan. Either you buy it or you don't play at all (unless you borrow from a friend who has bought the game). This led to increase in difficulty for games which were considered easy and short enough that gamers could finish them over a couple of days of renting it. Higher difficulty means more time has to be spent with the game in order to beat it, which requires more rentals or buying the game.

Sometimes, the difficulties are the same but named differently to be more or less encouraging depending on the region. For example, one region might have Easy, Normal and Hard while another has the same difficulties, but labeled Normal, Hard, and Super respectively.

Arcade

 * Black Tiger - The Japanese version (titled Black Dragon) features a greater number of enemies with stronger attacks, more aggressive bosses, more falling rock traps, and more expensive items.
 * Crime Fighters - The Japanese version featured a traditional lives/health gauge system, whereas the American version uses hit points that are gradually drained as time goes by. The Japanese version also has a back kick button that was removed from the American version.
 * Devil World - Not to be confused with the infamous Famicom game of the same name, this Gauntlet (1985 video game)-inspired overhead action game by Konami was released in America as Dark Adventure. The American version traded Labryna's and Condor's default guns (a bow-gun and a pistol) in favor of melee weapons (a sword and a whip), ditched the Gradius-style power-up system in favor of specific power-ups, and their health decreases faster than in the other versions. On the other hand, Dark Adventure has an additional character in the form of the spear-wielding Zorlock, allowing for up to three players.
 * Double Dragon 3: The Rosetta Stone - The overseas versions were made first and featured item shops where the player could purchase new playable characters, special moves and weapons (among other power-ups) by inserting more coins into the cabinet. Essentially Double Dragon 3 introduced the concept of Microtransactions in gaming long before it was employed by other developers. This feature proved to be rather unpopular among players, so when the developers worked on the Japanese release, they removed the item shops completely and allowed players to choose any of the four character types from the get-go, with all their moves usable from the outset (they did make the Hurricane Kick harder to pull off to compensate for this). In the Japanese version weapons are found lying on the ground waiting to be picked up, a huge contrast from the first two games where the player had to disarm enemies first.
 * Gradius - The overseas version (Nemesis) feature more aggressive enemies. To make up for the increased difficulty, the game throws the player a fleet of red enemies every time he loses a ship, allowing the player to refill his ship's power-up gauge.
 * Gradius III - The rare "World" edition had the full length "technical course" of the Japanese version with the difficulty of the "beginner" mode.
 * Haunted Castle - There were four versions of the game labeled M, N, O and P. M and O were the overseas releases, while N and P were Japanese releases. Version M in particular is the hardest of the four versions, where a single bone throw from the skeleton enemies in the very first stage will result in the player losing half of his health.
 * Jackal (aka Top Gunner) - In the Japanese version, the player's machine gun will shoot at the direction their jeep is facing, whereas in the US and World versions it will always shoot north. The grenade/rocket launcher works the same way in all three versions though.
 * Kid Niki: Radical Ninja had mid-stage checkpoints in the American arcade version, whereas the Japanese arcade version (Kaiketsu Yanchamaru) forced you back to the beginning of the level upon death. The NES/Famicom port had the same mid-stage checkpoints in all regions.
 * Shadow Force - The U.S. version added one-on-one segments after each stage (including the final one) that forced the players to fight each other (or in the case of a solo game, against a computer-controlled version of one of the main characters) before proceeding to the next stage, making it impossible to complete the game with a partner without credit feeding. To top it off, there's even an additional battle after the final boss fight where the last surviving player must fight against a revived version of a previous boss and if he loses this battle, it's an instant Game Over with no continues. The U.S. version also used a more complicated six-button configuration instead of the Japanese version's simpler three-button controls (the extra buttons in the American version were for moves that were originally done with different joystick/button combinations in the Japanese version).
 * The Simpsons - The American version is slightly more difficult than the Japanese release—the screen-clearing nuclear bomb item was removed, and you can't jump while carrying an item. The Japanese version also allowed players to add another "layer" to their health gauge by picking up food with full health.
 * Super Contra - The export version ends on one loop, whereas the Japanese version has a second loop in which the difficulty is set on the hardest setting (regardless of the game's actual settings) and continues are not allowed.
 * Trigon - The US version (Lightning Fighters), the game-breaking Homing Trigon weapon is no longer available in 1-player mode. On the plus side, it does have instant respawning when you die, although you still lose all your powerups.
 * Twin Cobra has a fair number of differences from its Japanese version, Kyūkyoku Tiger, but the one with the most dramatic impact on the game's difficulty is that Twin Cobra doesn't force the player back to a Check Point upon dying. The player's helicopter also moves a bit faster in Twin Cobra.

Family Computer / Nintendo Entertainment System

 * The Addams Family Fester's Quest - The European version made it easier by allowing Fester's shots to pass through walls and obstacles. This prevents the frustration of shooting at enemies in narrow passages with projectiles that don't go straight.
 * The Adventures of Bayou Billy - In the western version, anything in the driving stages causes the player's jeep to explode in one hit. The Japanese version (Mad City) just takes a chunk of life away. And this is one example. As a rule of thumb, anything that would help you is halved (like your attack and defense), and anything that would hamper you is doubled (like enemies' attack and defense) when compared to Mad City.
 * Adventures of Lolo II and III - The American versions of both games contained some puzzles lifted from older Eggerland games that were never released in America. The Japanese versions of these games, titled Adventures of Lolo and Adventures of Lolo II (the first American Adventures of Lolo consisted entirely of recycled puzzles, and was therefore not released in Japan) contained new, harder puzzles instead. However, some of the puzzles from the Japanese Adventures of Lolo also ended up in the American Adventures of Lolo III.
 * Battletoads - The Japanese version is a bit easier than the western releases, which is not saying much. Notably, Level 3 has lots of extra jump ramps, no midair ramps (and completely removed the island jumping section with the flashing exclamation mark) and doesn't speed up at the very end; similarly, the Hypno-orb in Level 11 moves slower. The player also has 5 lives per continue by default (instead of 3), which requires a cheat code to enable in other versions of the game.
 * Bionic Commando - The western version changes around the difficulty of certain areas a bit. Generally, the early areas of the game were made much harder and the later sections were made easier.
 * Castlevania 1986 - The original Disk System version in Japan (Akumajō Dracula) not only had a save feature, but also gave out morning stars earlier. The 1993 Japanese cartridge re-release took out the save feature, but added an "Easy" mode which starts the player off with more lives and power-ups.
 * Castlevania III Draculas Curse - In the western version, every enemy takes off the same amount of health, and the damage they inflicted increases in later stages, as with the first game. In the Japanese version (Akumajō Densetsu), different enemies take off different amounts of health, and the damage they inflict remains the same throughout the entire game. The western version also has more enemies in some rooms (such as additional bats in the last room before Dracula), and Grant's throwing daggers (with an attack range that reaches across the entire screen) were replaced by a stabbing dagger with tiny range.
 * Contra and Super C - The Japanese versions of both games had a Stage Select code. The ten-lives code in Super C was originally a thirty-lives code in the Japanese version as well.
 * Dr. Jekyll & Mr. Hyde - The two of the three town stages from the Famicom version (Hōma ga Toki) were replaced by recycled versions of other stages. Admittedly, these stages were most likely cut out due to their suggestive content rather than their actual difficulty, since the player could refill Jekyll's stress gauge by visiting a certain woman's apartment, who proceeds to pays him with cash while romantic music plays in the background (although, sometimes the opposite happens as the woman proceeds to drain Jekyll's stress gauge and steal his money instead). Nevertheless, their removal does affect the game's difficulty, since there's no other way to restore Jekyll's stress gauge.
 * Double Dragon II: The Revenge - The Japanese version has standard names for its three difficulty settings (Easy, Normal and Difficult), while the American version gives them fancier labels (Practice, Warrior and Supreme Master). Whereas the Japanese version features unlimited continues and allows the entire game to be played on any difficulty, the American version requires cheat codes to continue and restricts the game's length based on the setting (the easiest setting lasts only three stages, whereas the final stage is only accessible on the hardest level). There are other specific differences between the two versions as well: the disappearing platforms in Mission 6 are much easier in the Japanese version's Easy and Normal modes than in the American version's Warrior setting, while enemies have more health in the Japanese version's hardest setting than in its American equivalent.
 * Double Dragon III: The Sacred Stones - The American version adds more enemies and reduces the player's total health by ten points per character. On the other hand, the Japanese version changes the ending depending on which character survive the final battle, whereas the American always shows the full ending with all four characters regardless of whether they died during the game or not (including Jimmy, who only appears in a 2-Player game).
 * Dragon's Lair - The Japanese and European version were improved over the original American release by making the game faster and smoother, thereby reducing the difficulty level a notch.
 * Fist of the North Star - Originally released as Hokuto no Ken 2 for the Famicom, the American version features a few difficulty adjustments that ultimately makes it easier than the Japanese original such as making some of the sub-bosses easier to defeat and the ability to continue at any stage (the Famicom version only allows the player to restart up to the fourth stage).
 * Life Force - In the American version, a single player can have up to two attack drones (or one for each player in 2-Players Mode), whereas the Japanese version (Salamander) allows up to three shared between both players. On the other hand, the NES version got the Konami Code, which was not in the Famicom version.
 * Mega Man 2 - The American version had two difficulty settings: Normal and Difficult. The Japanese version only contained Difficult mode, and was deemed too challenging for most American players, explaining the change. The Wily Wars port for the Mega Drive was more faithful to the original Japanese version and had no difficulty selection.
 * Metal Gear 1987 - The European version has a minor, but rather crucial change from the Japanese and American versions. All three versions of the game have an item called the Iron Glove, which is obtained by defeating Machine Gun Kid. Ideally it's meant to break down certain walls with the player's punches when equipped, but in reality all of the walls that can be destroyed by punching can be done so without the glove, turning it into nothing more than an inventory filler. In the European version, they made the secret path that leads to Dr. Pettrovich's cell in Building 5 inaccessible without it, so the glove has a use in that version.
 * Ninja Gaiden III: The Ancient Ship of Doom - The American version removed the password system (being the only game in the series to have one), doubled the damage delivered by enemies (essentially reducing the player's health by half), limits checkpoints to only the beginning of a stage and made continues limited. The version included in Ninja Gaiden Trilogy for the SNES reverted the difficulty back to the same level it was in the Famicom version.
 * River City Ransom - The Japanese version (Downtown Nekketsu Monogatari) has three difficulty levels, whereas the western versions only has two. The "Easy" setting was removed, while "Normal" and "Hard" became "Novice" and "Expert" respectively. The option to disable player-to-player damage was also removed from the western versions.
 * Rush 'n Attack - The Japanese version was released for the Disk System under the title of Green Beret, which featured instant re-spawns after every death (instead of the checkpoint system used in the NES version), greater ammo carrying capacity for the player (9 instead of 3), limited continues (as opposed to none) and hidden underground shortcuts. To balance things out, the NES version starts the player off with more lives and all the weapons give out full ammo (as opposed to the Disk System version, in which they had to be accumulated one by one).
 * S.C.A.T. - Also known as Action in New York in Europe, S.C.A.T. is a rare example of an NES action game actually being made easier for the export market. The Famicom version, Final Mission, started the player with three hit points and would revert the player's weapon back to the default gun every time the player gets hit. In the NES version, the player starts off with six hit points and always keeps his or her weapon no matter how many hits he or she takes.
 * Section Z - The Famicom version was released on the Disk System and had a save feature that allows players to resume the game where they left off. The NES version on the other hand forces the player to complete the whole game on one sitting.
 * Super Mario Bros. 2 - Probably the most famous case of this trope. The original Japanese sequel was so frustratingly hard that Nintendo decided not to bring it to America, instead converting a completely different game called Doki Doki Panic into a Mario game. This is why Mario 2 is such an oddball in the series. The original sequel did eventually get released as "The Lost Levels".
 * Super Mario Bros 3 - The western version some subtle changes in its difficulty. In the Japanese version, if you were Fire or Raccoon Mario and you were hit, you'd revert to Small Mario (same as the original Super Mario Bros). This was changed in the American version where being hit while having fire or raccoon powers would revert you back to Super Mario.
 * Super Spike V-Ball - The Famicom version (titled U.S. Championship V-Ball) has a Tournament mode where the player compete against ten CPU teams (five American teams, three World Cup teams of randomly-assigned nationalities and two special matches) that could be adjusted by up to three difficulty settings (Easy, Normal and Hard). The NES version took out the difficulty settings and split the Tournament mode into three modes: Practice (only one match), American Circuit (consisting of five teams) and World Cup (seven teams, including the special matches and two added teams that were not in the Famicom version).

Super Famicom / Super NES

 * Brain Lord - Monsters were beefed up in the U.S. version.
 * Contra III: The Alien Wars - The Japanese version (Contra Spirits) had a couple of cheat codes (namely a thirty-lives code and a stage select) that were removed from the overseas releases. Moreover, the Japanese version allows the player to fight the True Final Boss on Normal, whereas the overseas versions only allows it on Hard.
 * Donkey Kong Country, another Rare game, had numerous small changes in the Japanese version (Super Donkey Kong) that made it slightly easier in a few levels.
 * Donkey Kong Country 2 - Similarly to the first game, saving after the first time in Kong Kollege only costs one coin in the Japanese version, not two. However, Funky's Flights still costs two coins.
 * Final Fantasy IV - The American version (titled Final Fantasy II since it was the second game in the series released overseas) was significantly easier than the Japanese version. It eliminated a number of character abilities and items, simplified the removal of Standard Status Effects, and made most of the bosses easier. A few months before its release, Square released an "Easytype" version of the game in Japan, based on a prototype of the US version that was even easier than the US version with things like Ribbons that absorb all elemental attacks on top of protecting characters from status aliments.
 * Illusion of Gaia - In the Japanese version, herbs fully recover your health. Also, you don't have to, and the earthquake attack can be used to stun a boss.
 * The 7th Saga - The American version is legendary for being obscenely hard and featuring insane level-grinding. The Japanese version on the other hand, reduced the average stat gains per level for player characters compared to the American version. This also added an Unwinnable situation, as they didn't tone down the stat gains your rivals get as bosses based on your level, so leveling up too much can literally make them too powerful to beat However, there's a loophole the player can take advantage of here. The rival's stats are based only on the main character's level. Therefore, the player can get around their stat gains by only leveling the companion character and making him or her fight the rivals instead.
 * Super Double Dragon - The Japanese version (Return of Double Dragon) has three selectable difficulty settings (Easy, Normal and Hard), whereas the American version doesn't have any. However, the difficulty of the American version is harder than the hardest setting of the Japanese version. Enemies have more health and weapons such as incendiary bombs and knives are more lethal. The American version also recycles boss characters more often and some of the added moves in the Japanese version, like the multi-hit Hurricane Kick and the ability to catch your boomerangs or exchange weapons on the ground, were not implemented yet in the American version. On the other hand, the Japanese version is slightly longer, with two extra areas added to the final stage.
 * Super Mario World - Very minor changes are noticeable between versions. The bonus level "Funky" in the Japanese version had three green berries which add time to the clock. Western versions added six more green berries.
 * The Twisted Tales of Spike McFang - The American increases the defense of enemies, making level grinding obligatory if the player wants to do more than scratch damage to bosses. Many enemies turn into Boss in Mook Clothing thanks to this. It also removes the Level Up Fill Up mechanic and the option to restart with full health in the beggining of a area if you die.

Nintendo Game Cube

 * Luigis Mansion - The Hidden Mansion mode wasn't too impressive in the Japanese and US versions, with merely rooms being a bit darker and some other minor tweaks. The PAL version though... completely redid most of the game. In this mode, you got the whole mansion mirrored, more (and harder) enemies in rooms, more treasure like golden mice, bosses with new attacks (rocking horses in first battle went diagonal, you rode on the Poltergust when against Boolossus, and Bowser's mines exploded instantly in some cases), and annoyingly... you had to beat the Hidden Mansion to get an A grade.
 * Resident Evil 4 - The Japanese and European versions have an "Easy" setting that was not present in the American release. This also applies to the PS2 and Wii versions.

Wii

 * Fire Emblem: Path of Radiance - The Harder Than Hard Maniac mode was removed and replaced with an Easy mode in the American version. Then again, the 255% crit chance forge bug was removed, and upper-tier enemies can crit a lot more. Note that Radiant Dawn also had an "easy" mode added to the US release...which was actually the Japanese normal mode. The American "normal" mode is actually the Japanese hard mode.
 * Super Smash Bros. Brawl - The PAL version, in addition to bug fixes, made all the challenges skippable via Golden Hammer. No more hammer-proof challenges.

Game Boy

 * Castlevania II Belmonts Revenge: All versions have two sub-weapons, but in Japan they're the Holy Water and the Boomerang Cross, while in the overseas versions the Cross was replaced with the Axe.
 * To clarify: The Holy Water and Boomerang Cross are generally considered the best sub-weapons in the series—used properly, they can hit multiple times for absolutely massive damage and in some games the Holy Water can trap enemies in helpless hit-stun. The Axe... is generally considered borderline useless—it does decent damage, but it has a weird arcing trajectory that makes it hard to hit anything not positioned above you.
 * Operation C - The Japanese version (simply called Contra) has the Stage Select mode activated by default, while the overseas releases required a cheat code.
 * Pokémon Red and Blue - There is an infamous glitch where surfing on the east coastline of Cinnabar Island (or Seafoam Islands) yields strange Pokémons, depending on various factors. The most well known example of this is MissingNo., which, while causing nasty side effects like corrupting the player's Hall of Fame, is also useful for duplicating items to cheat. The glitch can also be used to find and capture Safari Zone Pokémon easily this way. However, apparently this bug was already discovered before the games were released in Spanish (and possibly other languages), where the bug was fixed. This makes the game slightly harder for the small percentage of the player base who used this cheat.

Game Boy Advance

 * Mario & Luigi: Superstar Saga - In the Japanese version, Heart Blocks were in some certain places where you could get a free heal. The North American release, which was released earlier, did not have this feature.
 * Metroid Fusion - The Japanese version actually came out after the American version, so Nintendo took the time to add selectable difficulty settings. There are three, Easy through Hard, and they work much like the ones in Zero Mission. Easy mode is of particular interest to speed runners because it eliminates many of the random factors that can cost time.
 * Pocky & Rocky With Becky - Originally released in Japan as KiKi KaiKai Advance in Japan, the characters were upgraded from One Hit Point Wonders to Two Hit Point Wonders, and a password system was added.

Nintendo DS

 * Mario & Luigi: Partners In Time -Like the GBA original, the US version was released first, making the Japanese version easier in most extents. The items are cheaper in the Japanese version, many bosses have half the health, and the badges and gear have more stat boosts. Heck, even things like the UFO to target in certain boss battles staying in one place, the save point being inside a shop in one area, certain bosses using less effective healing items, and three of the bosses having counterattacks.
 * Pokémon HeartGold and SoulSilver - Due to European ratings board aggression against any reference to gambling, the overseas releases did not feature the original Game Corner. Instead, everyone else got a game that is best described as "minesweeper + sudoku + (noticeably less) Luck-Based Mission". While attempting to earn prizes early would be a pain if you could actually lose money, it is instead fairly easy to get Dratini when you can't.

Sega Mark III / Master System

 * Ashura - An overhead action shooter that was released as a Rambo in the United States and as Secret Command in Europe. The original Ashura version released in Japan was slightly harder, as some of the tougher enemies required more bullets to kill or were only vulnerable using fire arrows.
 * Black Belt - Originally released in Japan as a game based on Hokuto no Ken. While the difference are mostly cosmetic due to the change in characters and setting, one of the bosses (the fire-breathing giant Devil's Rebirth) was replaced with a new enemy (Gonta the sumo wrestler) who fights with all new attack patterns. Black Belt also has more health power-ups compared to Hokuto no Ken.
 * Captain Silver - The American version is two stages shorter than the Japanese and European versions and many enemy characters (including some of the bosses) were removed, resulting in an overall easier game.
 * Wonder Boy in Monster Land - Released as Super Wonder Boy: Monster World in Japan, the Japanese version gives all the enemy characters twice the hit points they have in the American version.

Mega Drive / Genesis

 * Castlevania Bloodlines - The US version was made harder.
 * Contra: Hard Corps - The Japanese version (Contra: The Hard Corps) features a three-point health gauge, unlimited continues and numerous cheat codes not present in the overseas releases. The European version is almost the same as the American in terms of difficulty, only it gives out less continues to compensate for the slower playing speed that makes enemies more predictable.
 * De Cap Attack - Released in Japan as an anime Licensed Game, Magical Hat no Buttobi Turbo! Daibouken. Decap Attack featured a Life Meter system where the Magical Hat version made the player a One-Hit-Point Wonder. To compensate for this, the stages in Decap Attack were redesigned, with more and harder enemies.
 * Dynamite Headdy - The player starts with 3 continues in the Japanese version but none in the American version (additional continues can be earned in both versions) and had a few other tweaks that made the American version more difficult, like Trouble Bruin's energy balls, which can't hurt you in Japan, but will in America. On the other hand, Twin Freaks, one of the hardest bosses in the game, has twice as much health in the Japan version (but the player can cheat against it, unlike in the American version).
 * Rocket Knight Adventures - All versions have the same four difficulties, but the names are different: the Japanese version has "Normal", "Hard", "Very Hard", and "Crazy Hard". In Europe, "Normal" was renamed "Easy". And in the US, the same difficulties were called "Children", "Easy", "Normal", and "Hard". Notably, in the other versions, Very Hard and Crazy Hard require codes to unlock, but in the American version, all four difficulties are immediately selectable.
 * Streets of Rage 3 - The difficulty levels were adjusted between the Japanese and American releases. The Japanese version had Easy, Normal, Hard, and Very Hard. The American version removed Very Hard, but at the same time, they buffed up the difficulty levels by one. Easy is equal to the Normal level from the Japanese version, Normal is Hard, and Hard is Very Hard. On top of having a harder game, enemies in the American game did more damage to you on harder difficulties while damage was fixed no matter what in the Japanese game. If that wasn't bad enough, Easy mode on the North American version only lets you play up to Stage 5, after which you'd get a fake ending and are encouraged to try again on a harder level. This could be averted through the use of cheat codes. The Japanese version let you beat the game on Easy.
 * If that wasn't enough, the American version also gave the bosses more health depending on the difficulty. The most glaring example is the final boss in round 7A, where, in hard mode, he has nine health bars.
 * The game also pulls this trope in reverse for the special attack and dodge system. The Japanese version has you lose more health if you used a special attack without a full power meter and the roll move doesn't make you move far. Streets of Rage 3 outside of Japan improved these mechanics where special attacks now don't sap a lot of health without a full charge and the roll mechanic pushes you a lot further to avoid attacks. These improved mechanics are encouraged to be used all the time due to the adjusted difficulty outside Japan.
 * Wonder Boy in Monster World - In the Japanese version (Monster World III) Death Is Cheap—it warps you back to the last inn you saved at and charges you the normal inn fee (you can even just kill yourself if you don't feel like walking back). In the English version, if you die, it's Game Over. (The TurboGrafx-16 port, Dynastic Hero, uses the death mechanics of the Japanese version in all regions.)

PC Engine / TurboGrafx-16

 * Exile - The game was panned for being "too hard" in Japan, so Working Designs tried toning it down a little... making the game a cakewalk in the process. The reverse happened with its sequel, where it was basically made pretty close to Unwinnable.
 * J.J. & Jeff - An Americanized version of Kato-chan & Ken-chan, a side-scrolling platformer based on a Japanese comedy duo of the same name. The changes to the game were mostly cosmetics, but one change that actually affect the play mechanics a bit was that the player's fart attack was changed into a spray can, changing it from a back attack to a front attack.

PlayStation

 * Crash Bandicoot 3: Warped - The difficulty was altered both ways. In the PAL version, the power you get for beating the final boss (which enables Crash to run faster) is more effective than in the American version, making the timed goals easier. However, the requirements for one of the time trials (on which you can't use that power) were revised. One of the enemies was given an extra attack and another was given the (unique outside of boss fights) ability to survive Crash's first attack in the PAL version, although neither makes the enemies significantly more difficult to beat and the second might have been done solely so they could include something which the American censors might have considered too crude for a game aimed at all ages.
 * Final Fantasy VII - Two optional bosses were introduced for the export versions that later made to the International version in Japan: Ruby WEAPON and Emerald WEAPON. Emerald had the Aire Tam Storm, which does 1111 damage for every materia the player uses; of course, nobody knew this, so you'd better just hope two of them are Final Attack-Phoenix. It's also a Marathon Boss, but in this case, that actually is difficult (after 20 minutes, there's a Nonstandard Game Over) if you don't have the Underwater materia. Ruby, by contrast, takes two of your party members out. If you use Knights of Round on Ruby, it responds with Ultima. (You can, however, equip Ultima-Elemental to actually absorb non-elemental attacks.)
 * Metal Gear Solid - The export versions has four difficulty settings (Easy, Normal, Hard and the unlockable Extreme mode), whereas the Japanese version only has two settings (the standard one, which is identical to the export version's "Easy" mode, and a "No Radar" mode that is also identical, but with the Soliton Radar turned off). The codenames used to evaluate the player's performance in the Japanese version were transferred over to the Hard and Extreme modes in the export versions.
 * Persona - A more difficult alternate quest was cut from the US release. Also, in a failed attempt at making the game easier, they made it harder by reducing the encounter rate to 1/3 and tripling the EXP gained from battles. The problem is, rather than their intended goal of leaving the player with the same amount of EXP with fewer battles... they forgot to factor money into it, leaving the player permanently poor and unable to afford the standard weapons.
 * The reduced fights also meant less chance for negotiations which allowed the player to create new Personae, get items, and stop fights whenever possible.
 * On the other hand, the reduced encouter rate also meant that characters had a better chance to take advantage of their SP (Spirit Points used for magic) regenerating while walking outside of battle, making SP management and healing easier.
 * Resident Evil - The Japanese version has an auto-aiming function, as well as more ink ribbons and ammo available. The developers thought of furthering the difficulty in the export versions by making storage boxes not linked, meaning that items that were stored in one location couldn't be retrieved in another. While this was only implemented in review copies and not in the retail version, the idea was brought back to the "Real Survivor" mode featured in the GameCube version.
 * Resident Evil 2 - In the American version, some of the item and enemy placements are different from the Japanese release. The U.S. version's difficulty setting is featured as an extra mode in the Dual Shock-compatible re-release of Biohazard 2.
 * Silhouette Mirage - The U.S. version was borked entirely, as it originally featured the prototype of the color-swapping mechanic that later went into Ikaruga.
 * Tomb Raider 2 - The Japanese version features much weaker enemies and have certain traps removed.
 * Final Fantasy VIII has Guardian Forces drawable in every boss encounter in the final level in case you missed any the first time around, but missing these the second time around makes them a Lost Forever for good. The Japanese version did not give players a second chance in drawing a Guardian Force in the final level.

PlayStation 2

 * Devil May Cry 3 - All the difficulties were bumped up by one notch for the original US release, so Easy was Japanese Normal, Normal (the only difficulty available at the beginning) was Japanese Hard, etc. The game was no cakewalk in the original release, and the "adjustment" elevated it to hair-tearing for first-time players who didn't want to drop down to Easy. The Special Edition re-release restored the original difficulties, with the American Hard becoming Very Hard.
 * It also restored the option of using the Gold Orbs (let you revive right where you died) from the JP version... but still let you use the US version's Yellow Orbs (let you revive outside the last door you walked through, like the original DMC).
 * Final Fantasy X - The PAL version added the Dark Aeons, which are evil versions of your summons that function as a total of 8 Bonus Bosses (9 if you include Penance, who is unlocked after beating all of the Dark Aeons). However, they're at a higher level than the actual Endgame Bosses- in fact, most guides basically come out and say "Your party for these fights should have AT LEAST 9999 HP, their fully activated Celestial Weapons, and the following very difficult to get armor perks..."
 * They're there because the PAL version is based on Final Fantasy X International, rather than the US version or original Japanese release, to make up for the delay and the technical issues of porting an NTSC game to the PAL image standard.
 * Ico - The Japanese and European versions were released after the American one and featured an increased difficulty, in addition to other bonus content. Notably, a few puzzles were lengthened by adding trickier bits, and the enemies are a lot faster and more aggressive - spawning more frequently than they did in the American version (where they only spawned if the player left Yorda in a different room or at scripted events).
 * Metal Gear Solid 2: Sons of Liberty - The American version was the first version released. The Japanese and European versions later added a questionnaire at the start of the game that affected, not only which difficulty levels the player could choose, but also whether or not the player skips the Tanker chapter and starts right off at the Plant chapter. The European version also featured an unlockable "European Extreme" setting that was even harder than the already Harder Than Hard "Extreme" setting. The E-Extreme setting was later added to the Substance version in all releases.
 * Metal Gear Solid 3: Snake Eater - Like the previous game, an E-Extreme setting was added for the European version, which was also featured in all version of the Subsistence update.
 * Mr. Mosquito - In the game you fly around as a mosquito in a huge-to-your-perspective house, sucking blood from its inhabitants. In the Japanese version, you could suck from any exposed skin, but in the American and European versions, you could only suck from small designated points on the body, some of which were literally impossible to reach without dying.
 * Shinobi- The Japanese and European version had the following difficulty settings: Easy, Normal and Hard. Easy was removed entirely in the US release, which shifted the collectables from Normal to Hard and added in an extra "Super" difficulty with the Hard mode collectables. Super is the only difficulty where default character Hotsuma can't kill the later bosses in one hit.

PlayStation Portable

 * Dissidia: Final Fantasy - A bit trivial, but the difference in damage for most attacks between the American and Japanese releases is at least a single hit point.
 * Crisis Core - In the Japanese version, if Zack is KO'd during a side mission, it is a Game Over. In the US version, the game treats you as if you abandoned the mission and return you to the save point.

Xbox 360

 * Death Smiles - The American runs at around 150% the speed of the Japanese version, making it harder and preventing people from accurately comparing scores across regions—an unusual change considering that American players are, on average, less experienced with and proficient at the Bullet Hell genre than Japanese players. In a moment of Tropes Are Not Bad, the developers have stated that the US version is the game they had intended to make from the start, and some parts of the Japanese version were complained about as too slow.

Personal Computers

 * Age of Pirates 2: City of Abandoned Ships - The Russian version features three difficulty sliders - difficulty, rate of experience gain for the player, and rate of experience gain for enemies (ie how the much ahead or behind the level scaling will be). The English version lacks the latter slider altogether and it's set in the config files to the lowest possible value, making some parts of the game too easy and others (non-scaled) seemingly overly difficult in comparison.
 * Combat Arms - In the Korean version, if you played the mission with the Sand Hog, one of the enemies had dynamite strapped to themselves and tried to run into you. The North American version did not have that.
 * Dungeon Fighter Online - When Nexon released the American version, they upped the EXP requirements for levels by THREE TIMES the amount required in the Korean version. Not that this changes the difficulty all that much, but it does make for a LOT of grinding to level up. So while you'd only be at level 20 on the American version, someone on the Korean version would be close to level 35.

Multiplatform

 * Catherine (PlayStation 3, Xbox 360) - The game was so difficult that a patch was released to make it easier. In the Japanese version, the patch can be turned on or off once installed, but the American version comes patched and it can't be turned off. Also, the "Undo" ability, which allows you to rewind up to ten of your last moves, was added to Normal difficulty in the American version.
 * Toy Story (SNES, Genesis) - A password continuation system was added to both, Japanese and PAL versions, not present in the American.
 * The early Guitar Hero and Rock Band games have a rare unintentional version of this trope. Due to a bug the game seems not to register some of the strums above a certain strumming speed, in extreme cases only registering about half of a players strums. While details are uncertain it seems the bug is linked to the television refresh rate, with lower refresh rates having a higher tolerance for strumming speed. Since PAL mostly uses a 50 Hz refresh rate compared to NTSC's 60 Hz you can get away with strumming a little bit faster. This means that in songs that have very fast strumming it is much less difficult to get a Full Combo while playing on a PAL system.
 * Due to NTSC's refresh rate, however, one song (Trogdor) is completely unable to be Full Combo'd on Expert or Hard on NTSC, ESPECIALLY NTSC PlayStation 2. Most of the documented F Cs for either difficulty are on PAL PlayStation 2 through the use of SwapMagic (or being in Europe or a PAL-using area).
 * Kirby's Avalanche and Dr. Robotnik's Mean Bean Machine (both games being graphically modified versions of Puyo Puyo made for the foreign market) had a much shallower difficulty curve than the original.