I don't know if there are any retro fans out there, but there's a cool emulator I've been playing for a while called Happy bay free game center. It has over 1000 genesis, SNES, neo geo, advance games, all free. The beauty of  this app is the roms can all be downloaded there and then straight from the app and played instantly, and I've had  no issues with bad ROMs as they all seem to work and play perfectly ( I had this app on my old Arnova, and the games play much faster on my nexus). I got the apk from happy bay.mobi; you can choose to download the games individually, or just d-lo the game centre app, I did the latter for convenience, as they're all in one place. It's got all the best retro stuff:final fantasy, metal slug, street fighter etc. (It's not on the Play store, so will need to allow non market apps) has anybody else tried this?