Bitfighter is a game that feels a little like Asteroids on steroids. It's a multiplayer space-based combat and strategy game, featuring customized ships, multiple game modes, cool retro graphics, and smooth network play. It also includes a full featured level editor, Lua scriptable bots, and other cool features. It has a very active development team, so the game keeps improving.
Chicken Invaders 4 is a game in which you must resist an invasion of chickens from outer space. It features cooperative play with up to four players, 12 star systems to explore, 120 waves of invading chickens, a wide variety of weapons with upgradeable power levels, 30 unique bonuses, and 20 secret features.