MAME 2003 Plus supports thousands of arcade games, but not all 0.78 games run perfectly. It focuses on classics (CPS1, CPS2, Neo Geo, early 90s). Neo Geo requires the neogeo.zip BIOS in the same ROM directory.
For (the libretro core commonly used on RetroArch, Lakka, and retro handhelds like Anbernic devices), you need a specific ROM set version: MAME 0.78 (or 0.78u2 / 0.78 merged). mame 2003 plus roms
If you’re using a different device (e.g., Raspberry Pi, PC, Miyoo Mini), always verify the core version in RetroArch → Information → Core Information. MAME 2003 Plus supports thousands of arcade games,