In the 3DS modding community, "ROMs" typically appear in two main formats:
There was never a physical cartridge release; it was an eShop-exclusive title. The "ROM" Experience: Performance & Stability isaac 3ds rom
If you never bought Isaac on 3DS, your best bet is to purchase Rebirth on a modern platform. But if you are a digital archaeologist with a modded New 3DS and a desire to play a flawed, fascinating port with stereoscopic 3D tears and poop monsters—then you now know exactly what you are looking for. In the 3DS modding community, "ROMs" typically appear
These are raw, decrypted dumps of the game cartridge or digital file. While they are the standard "ROM" format, they cannot be recognized directly by a 3DS system. Instead, they are primarily used with emulators like CIA (.cia) Files: Standing for CTR Importable Archive These are raw, decrypted dumps of the game
Before you track down a ROM, keep in mind that the 3DS version is often cited as one of the more "interesting" ports—for better or worse.
The "File System" containing the game's assets, music, and code. Extracted .exe FS: The executable portion of the game data. Extracted Manual/Banner:
If you're interested in playing The Binding of Isaac on your 3DS, you can still find the ROM online. However, be sure to only download ROMs from reputable sources to ensure that you're not harming the game's developers or violating any copyright laws.