Echoes

From Binary Zoo. It seems alot like Geometry wars, though it's focused clearly on it's roots, Asteroids. I really like it so far. There's an overall ship health combined with "depowering" when you get hit (seems popular for these sorts of games). Differnet colors of asteroids have different properties and there's other items that show up. Movement/firing is just like Geometry Wars/Ultratron.

http://www.binaryzoo.com/games/echoes/index.htm