You're right, "not much," but fun! Simple concept and well executed.
The background scrolls a bit too fast -- especially for stars in space.
Giving the meteors an animation for when they hit the surface would add some polish, I think.
I'm a big shmup fan, so --inevitably-- I thought that some more "bullet patterns" would have been cool for the meteors.
All in all, though, I enjoyed it. I played and beat it on insane mode.

--mister. jones