eh...
Not too bad, but there's LOTS of room for improvement. For example, while flying the stolen ship, it's impossible to dodge several of the obstacles. And the sudden spawn of nearly a half-dozen of the pink enemies shortly after that point causes killer lag.
In fact, lag is pretty much a constant problem, even on Low quality. I can't find a reason for this--even when there are scores of enemies on screen, the art is NOT so detailed as to cause THAT much lag. I'm guessing you've either set up some extraneous ActionScripting, or you have layers that just don't need to be there, or something.
Work on it, and you could have a killer game here.