To run Neo Geo games on MAME, you need to have the correct BIOS files. The MAME emulator uses these BIOS files to mimic the behavior of a real Neo Geo console. The process works as follows:

To avoid headaches, follow these golden rules:

The BIOS contains the operational code from the original SNK Neo Geo hardware. Without it, MAME cannot simulate the hardware required to run games like Metal Slug or The King of Fighters .

: Modern neogeo.zip sets often already include several versions of UniBIOS (e.g., uni-bios_4_0.rom ).

should match the version of the MAME executable you are using. petrockblock Managing Neo Geo Settings

C:\MAME\roms\neogeo.zip