I must say that I really, really enjoyed playing your game. The whole thing is pretty much perfect and there are only really small things I would have added if I was you, such as the possibility of being abble to toggle the quality during playing, because sometimes it can get a little laggy when having dozens of enemies on your screen and I would have also liked to pause the game even when not being right next to your ship.
You did a wonderful job and obviously gave your best. Different weapons and upgrades provided variety and didn't make the game boring - not even during my second playthrough. The ending also added a nice touch to the whole project and made it seem even cooler.
Very well done!