Really fun game! :D
I've actually been wanting to play Geometry Wars 2 recently but can't find it anywhere, this was very much the kind of thing I was wanting from it XD I thought the difficulty was really nice, not too easy but not over the top hard either. The upgrade system was cool, and I liked that by the end of the game you're in a pretty OP state :D
Not really much to say in the way of criticisms, would have maybe been cool to have another enemy type or two, and I'd have been happy for it to have been longer :)
Great job!