I downloaded a few M.A.M.E. games and tried to get them to run on my Raspberry Pi running Retropie v4.2. I tried about every emulator I could think of that comes with the Retropie and I could not get any of the games to load. Can anyone shed some light on what I could be doing wrong? Is the emulator specific to the game or is there a generic emulator that I can use that will run all M.A.M.E. games? Here is a list of some of the games I downloaded:

Galaxian
Defender
Spy Hunter

Any help would be greatly appreciated.