Excellent
I'm finally reviewing this after playing once or twice a day for the last couple days, and finally beating it today. I'm not easily hooked by any game, but this one did it. Hang on, this will be a long review.
I love the coherence of the game. The music, art, and gameplay fit remarkably well together. Not only that, but all three are great in their own right. The music gets my adrenaline going but has enough variation that it never really becomes annoying. The art is great too. It's minimalistic, but there's lots of nice detail on what is present. The gameplay was extremely difficult at first. I didn't realize that there was a slow down button at first and that really screwed me over, especially with the tail things. But once I got the hang of hitting just the right parts of the different enemies, things got a lot more manageable. I think that the learning curve of this game is pretty close to where it should be. That said, a little more in-game guidance would have been nice.
All that praise isn't to say this game is without flaws. There were some really problematic glitches. The game sometimes freezes up or blacks out, or I'd lose the ability to move in one direction. I realize it's really hard to track these bugs down, but they seriously detracted from the experience. My other big complaint is that some of the enemies seemed distinctly out of order, difficulty wise. The fat guys that shoot circles are WAY harder to deal with than many of the enemies that follow them. The guys that try to eat you are also more difficult to avoid than their shooting counterparts.
So... this game has some problems, maybe even enough to bump you from a 10 to a 9. But in the end, I'm really impressed by the job you've done. This game is polished, fun, and really well presented. Great job.