I got to Wave 11, highscore of 96 - sweet game!
It controls well although I sometimes found myself wanting to click the mouse to shoot/ram rather than pressing the spacebar. Adding more attack types would be a really fun addition. Also having control over switching your attack type would be neat, but that would take a little bit away from the the simplicity of the game which is something I really liked about it. Great job.
Check out my game if you get a chance!