Pretty fun
I thought it was a fun game. The only problems were the story (it sucked and was comprised of nothing but the idea that Nelkia is going to destroy the galaxy...) and the fact that almost all the enemies took one hit to kill.
Try making it a little more challenging. The last boss was the only thing that managed to kill me. Maybe make the little coins that give you life give you less than they do.
Oh, and I liked the music a lot.