Very neat little game! Kinda reminiscent of DSiWare games, I really enjoyed it for what it is, and I think it could be really be good as a short 1-2 hours game with new mechanics, maybe different types of projectiles, etc..
Also, I think the game's physics are dependent on framerate? Maybe I was just imagining things, but the distance between the projectiles seemed to change randomly, so that's probably it.
Great work, hope you keep exploring this concept!