"Rayman 3D" is actually a port of the Sega Dreamcast version of "Rayman 2: The Great Escape." That's a CD game ported to 3DS, so it's not impossible. So if it's an older game it might not be an issue. Might have to tweak the emulation a bit though. Game data on CD discs is a bunch of codes, just like on game cartridges/cards.