Any major problems you guys found?
You can see asteroids spawning in the middle of the screen every once in a while.
Might I also suggest (along with switching to the other ctrl key) you make the asteroids take one or two more blaster shots? As it is there's little reason to use the missiles. The blaster only takes a couple hits and is easier to aim and quicker to kill with.
Maybe also make the missiles heat-seeking (or I guess "asteroid seeking" since asteroids don't give off heat ).