hate to say..
what the other peoples reviews say are mostly true. You don't provide much a variety in enemies to kill, its too easy to dodge their attacks, and the levels go on for hours and bore you half to death- not to mention the background is nothing but stars in space.
Granted, i did see a difference in the weapons you gave- but the strongest weapon had you sitting in the back waring out your wrist because its all semi-auto fire.
i went straight to the hardest level to see how cool the boss may be- but instead i got half an hour of killing the same 3 enemies which dont live up to their difficulty level you placed them in.
Finally- after i had wasted half an hour of my life on one level- i gave up just to see what dieing would look like. It took forever to get my health bar to zero and when i did i was still alive. I had to wait till the kill score had added up all my points- then i died (which took about 5 minutes)
I can see you put most of your effort into the weaponry in this game- which is cool and all. but you really gota work on the game itself..