Captain, spock just poked me!
I enjoyed this game though the difficulty did not (noticably) increase throughout the game, and altough I think that is an essential part of any game I am glad you kept it slow as a rapid change of pace is often more annoying than challenging.
I liked the sounds, though the "receive" sound was a bit like a choir of angels and didn't add to the space age feeling of the game at all.
A little technicality, a space ship breaking up an asteroid on impact is like a car going straight through a brick wall, it MIGHT do it, but you're probably dead or worse afterwards. On the other hand I cannot suggest an alternitive since I would have complained about anything else I can think of, so just consider it the lesser of two evils :)