Not bad so far. The concept as a whole seems to work... well, not great, but okay.
You probably already know what problems it has but I'll go over the few I noticed... it seems that the spawning area when flying vertically isn't wide enough to fill the screen. Also, stars spawn more densely when you're flying slower.
It also appears that you'll need to spawn stars perpendicular to the ship on either side, because when you change direction quickly there's a blank patch of empty space there. Perhaps my idea for spawning stars was flawed to begin with... it might just be better to do it something like this:
<img src="http://i43.tinypic.com/amtvtg.png">
You could just set up those zones as static areas around the play area. It'd probably work better than trying to tweak my old idea into working properly.