Hi! I'm an admin from RetroAchievements, excited to see all the hype around here. Each achievement set will have specific files it supports, as visible in "supported game files". In the case of Earthbound, that encompasses a wide variety of translations as well as a few improvement hacks, plus the basic US version of the game. Usually games will have a much smaller number of supported files due to incompatibilities in the memory across versions complicating matters, as well as the achievement set dev being responsible for ensuring compatibility with the linked files. That said, hashing is based on the rom file itself, not the filename. In the case of SNES in particular, it's just an md5 hash of the (headerless) game file. Different romhacks may have their own sets, and there are some special inert patches available to enable challenge achievement sets, such as one for completing the game while avoiding the cameraman at every opportunity.

If you have any further questions, please don't hesitate to ask!

I think they work through by going by the rom name and then checking the database online. I don’t know if romHacks work, it really depends if the community added it. You have to make a (free) account on the website to track your achievements and link to your emulator. Some emulators work with it, some don’t. But I haven’t dug deep on my retropie/retroarch devices to know if they all work.

I have nes->psx on this device so I’ll be testing a lot tonight.

I know delta and PPSSPP in iOS have support for it, but Delta requires a patreon subscription to use achievements so I won’t be doing that.

They don't work very well unfortunately. They use a MD5 checksum to verify your game, which in the surface sounds great, until you realize that a lot of the newer setups (EmuDeck) for roms will offer to compress them into .7zip files (and other types) and then suddenly none of the games are recognized as the original MD5 checksum is different. So you cant compress any game, and not sure if they work with .m3u lists and doubt it will because most likely it'll want to .MD5 checksum the .m3u file.

Also, it needs to have an Internet connection the entire time, so this kills more portable device usage unless you are at home/4-5G. They claim it's to prevent people from cheating the achievement, but in the end if just becomes another block in usability.