I really like this game. Very easy to learn, and quick to play.
I think that it would be nice to get some better graphics, but it's not a killer. Some power ups or something else to do would be a bonus, but keeping it clean and simple is nice too.

The only thing that got to me was that in firefox and IE if you click out of the flash and hold down space it scrolls you to the bottom of the window and you end up dieing. If you put something so that if the mouse goes out of the flash it pauses it would really improve it for me.