My favorite all-time game, on the iPhone using the NES emulator. Controls aren’t the best but it works!
If you need games for the Nintendo emulator, just head on over to this ROM download site — there are over 900 of them. Some of them work well with the iPhone NES emulator, while some of them are unplayable. I’ve had good luck with Donkey Kong, Galaga, Galaxian, Pacman, Space Invaders, Super Mario Brothers, and Dig Dug.
I have loved playing Donkey Kong since I was a kid playing the original coin-op version. One day I have to convince my wife to get me the original coin-op for Christhis (er, Christmas).