2 Player Reactor is a fun little multiplayer game Haven't tried RoboDefense. I'm thinking I should get on it
possibly been stated previously, but as of now, the best games are emulated ROMs...
unless you're a puzzle/word game fan: HDOS / HDOS 2 are great... WordUp for those who like scrabble... tetrad for tetris fans
Heres some that havent been posted yet
Gem Miner = sort of like Motherload flash game, or iDig on iPhone
Graviturn Extended (favorite so far) Sort of like labyrinth, but it tells you how you are doing in comparison with everyone else (perfect for the overly competitive), not exactly formatted for droid though, but it works fine
Light Racer 3d (Tron-style, cool graphics), 3d version has better controls than regular version too.