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Working with the Right ROM

Related: Achievements for ROM hacks, Bonus Sets

Only one achievement set is allowed per game per console. This is true in cases of existing official revisions (ex. Rev A), official and unofficial fix patches, and over regions.

Bonus Sets are an exception to this rule, but are considered an extension to a standard set and follow different rules for what types of achievements are allowed.

ROM Selectionlink

Almost every game has multiple ROM versions out there, sometimes dozens. Often there are major differences under the hood to the point where for one game, one ROM will not be compatible with the achievements of another ROM of the same game. Thus, finding the best ROM for achievements is important and should be done carefully.

  • Region Selection: Where possible choose no-intro NTSC USA release ROMs, because 60 FPS is a smoother gaming experience. PAL European releases run at 50 FPS, and are to be avoided in most cases. NTSC Japan releases also run at 60 FPS , but is only the best choice if the game was a Japan-exclusive release. Needing to resort to a PAL European release game should be a last resort case (Europe-only exclusive), and is typically a very select few unique games from the entire console's library. The PAL/NTSC issue does not apply to GBA emulation, which runs all region versions at the same FPS.

  • No Mods: Do not use a ROM with a modded/custom launch screen like Mode7 and RisingSun have because it messes up RAM.

  • No Trainers: Do not use a ROM that includes an integrated cheat feature. These are most often refereed to as after-market ROM trainers, are not official, and not in any way supported by Retro Achievements.


No-Intro ROMs are the preferred type of ROMs to be linked in the RA database, and should be the ones that you should use to make your set where possible. They filter out bad dumps, hacks, fakes, overdumps, underdumps, etc. and only display the ROMs that are most accurate to the original cartridge. No-Intro ROMs can be identified by the following naming scheme:

Game Name (Region) (Available Languages if Applicable) (Current Revision if Applicable) Example: Diddy Kong Racing (USA) (En,Fr) (Rev A)

GoodTools Game Name (Region) [!], as well as some of the Game Name (Region) (Rom Dumper Group) ROMs from an earlier era might match those in the No-Intro database but it is not guaranteed.

You can verify that your ROM checksum matches the No-Intro database here. Unfortunately some of the RA Emulators don't calculate the checksum correctly (namely NES) so you may need to find your ROM checksum from another source.

Translation patcheslink

(see also: ROM Localization Policy below)

English is the Primary language of RetroAchievements. Translation Patches are sometimes applied by developers to non-English titles as the main MD5 for an achievement set where no licenced English version exists. In these cases patching instructions will be provided in the forum thread of that title. Providing an up-to-spec translation patch for an existing title is possibly allowed to make a game more accessible to other native language speakers. You must deep-memory inspect your translation contribution against the core set and submit it for approval before handing it over to the developer of the set for posting in their thread along with the game.

Sometimes translation patches may critically differ from the developer MD5 in memory differences that you may find online. Before linking these patches check with the original developer or do deep memory tests to ensure total compatibility. You can link translation patches you find online to core sets as long as the game's core achievements all function correctly and do not make the game more or less difficult.

ROM Localization Policylink

As English is the primary language of the community, English ROMs are preferred. When choosing which ROM to build achievements out of various regional versions we give priority to No-Intro US ROMs for non-handheld consoles and European ROMs for handheld consoles.

We welcome and would like to continue improving our support for all regional versions, especially Japanese (as the majority of our game library was created in Japan). Also, some users simply prefer a specific regional version of a game and it is better to include broad support so that any good ROM can link to a good entry and give appropriate achievements.

When looking at how games with regional versions are handled our standard is one entry per game per console. It is ideal that if one loads up the US or Japanese version of Donkey Kong, Pac-Man or Contra, they will earn the same achievements from the same entry. But there are some situations where it is better for our library and players to split off regional versions into their own unique entry. If the community has reason to believe that it's better for an entry to be split it can be reviewed and approved by the developer team after a discussion and vote.

Tip: For games with text-triggered achievements (especially RPGs) it's recommend to find an event flag instead of hooking onto text or text ID. Text presentation varies between regional versions making multi-region support difficult.

Localization Differenceslink

The types of changes made during localization (most commonly from Japanese to English) can vary wildly. Any of the following changes may result from a localization:

  • Little or no change at all;
  • Passwords replace battery saves;
  • Bugs fixed;
  • Light or extensive translations;
  • Light or extensive cosmetic changes including elements considered offensive censored, sfx changes, or licenced assets being made generic, or unknown characters becoming Nintendoed (e.g. Tetris Attack, Super Mario Bros. 2);
  • Stages added, modified or removed;
  • Game physics and game mechanics modified;
  • Game modes, difficulty levels and game options added or removed;
  • Cheat codes or debug modes added or removed;
  • The game is rebalanced making it harder or easier, sometimes significantly;
  • Two games are combined into one;
  • And more.

Because of this variance and to avoid filling the database with unnecessary duplicates our goal is to minimize the number of split sets. For a set to be split it needs compelling reasons; we take great care to determine when to approve these splits.

Splitting out a regional entrylink

1. Getting approval through #revision-voting is

Approval follows the same flow as revision votes, such as posting your plan in the forum and the #revision-voting channel in Discord; allowing time for discussion and waiting 72 hours for majority approval is necessary.

Remember the goal to reduce duplication in the library; only allow a set to be split when it is strongly preferred.

The developer who intends to split a set should make a strong case for why the set deserves a new entry and why it's not possible to create the intended experience within a single entry.

Developers wanting to split sets are expected to act in good faith. Sets should be split for the betterment of our game library and the community and not as self-indulging way to remake a set or chase freebie dev points.

2. It might be acceptable to split a set iflink

  1. There are major aesthetic changes to the point where it could be mistaken to be an entirely new game.
  2. There are major balance changes such as significant changes in difficulty.
  3. There are major content changes such as new game modes, heavily edited stages, new abilities, etc.
  4. There are major mechanical changes.

Examples of games that qualify:

  • Awaiting examples of precedent

3. It's probably not acceptable to split a set whenlink

  1. The gameplay, balance, game content or mechanics are mostly unchanged.
  2. The various versions examined (such as Rev A) are within the same region.
  3. One region is slightly easier/harder than the other.
  4. The only change is a translation or name change.
  5. Minor or moderate cosmetic changes.
  6. Cheat codes or debug modes are added or removed.

Considering all this, it is still be up to the collective judgement of the developers.

Examples of games that (probably) don't qualify:

  • Super Mario Bros. (NES); the J and US release is the same file.
  • Earthbound, Chrono Trigger, Bionic Commando (NES); the (main) differences here are light cosmetic, translations and censorship.
  • Rockman/Mega Man (NES); the main difference being a few sfx changes and a new title and title screen.
  • The Legend of Zelda (NES), A Link to the Past (SNES); besides translation, the main difference are in the US release a number of bugs were fixed.
  • Contra (NES); the Famicom version has animated backgrounds, more images, a stage select mode, etc. The E version has a new name Probotector and characters and enemies are sprite swapped with robots.

4. After a set is approved to be splitlink

It is not acceptable to simply duplicate sets into split off entries. Split off sets should be treated as a new entry and not a sub-set (where Bonus sets are sub-sets). They should have a different feel, pacing and challenges that speak to the unique features of the game that caused it to be split off in the first place.


Last 10 changes on this page:

  • [2019-08-13 19:49] Kvon: Working with the right rom: text hooking tip added
  • [2019-05-03 11:30] meleu: typo
  • [2019-05-03 10:55] meleu: merge "ROM Localization Policy" into here
  • [2018-11-17 08:07] Kvon: changed one word, for clarifcation
  • [2018-09-17 17:56] meleu: capital 'R' in the title (Right)