it's a good game. jonathanasdf is right- it doesn't bring anything new to the table, but, like the original asteroids, it's loads and loads of fun. I don't agree with the choice of music- a power ballad theater rock song doesn't strike me as appropriate, and the song gets rather boring and repetitive quickly. anyone who disagrees with my classification should listen to Journey- this song sounds like something they'd perform. That may be a matter of taste, but I would suggest something with an electronic or techno air, such as the band Danger.
as far as suggestions for improvements go (that are not matters of taste ;) ), I would suggest increasing the speed of the 'roids over time, maybe adding a physics engine for asteroid-asteroid collision, and maybe increasing the number of shards or particles an asteroid produces when blown up. but these are suggestions, not commands, and your game still rocks.
to sum up, you said it was fun to make. I say, it's fun to play. Keep up the good work.