This is really really fun. I get the impression that you had to cut a lot for time, but spent every minute you could making the core of the game look and feel awesome. The weapon transformations look great, and shots have a nice oomph to them. A lot of what's missing you seem to have a good handle on and covered on the game page.
This one has a lot of potential for further development, the base of what you have is real nice, even once I realized there were probably going to be an infinite number of random stages, I still played a few more for the fun of it.