After some fiddling, I was able to back out of the black screen on startup and go to windowed mode. I really enjoy the game and the powerup/combo system. This is the most addicting game since Jetpack Joyride!
The only thing that is frustrating is that I don't know how to back up on waves. I'm stuck on Wave 20 since I got some huge powerups and then died, so I'm no longer powerful enough to last more than 20 seconds or so.