Man, this game is awesome. I've never seen something like that. It was very hard, though. I could made it until wave 25. Was that good?
The only thing that I didn't like was the fact that when you get shot, the screen goes red (blood). That's actually cool, but when you get shot too much (almost diyng) the screen goes too much red. You can barely see something. It shoud be transparent or something.
Anyway, 5 out of 5. Great game.