Pretty fun game, great graphics, everything runs smoothly, but it's a little easy. And that's not always a bad thing, but I beat the last boss without getting hit a single time. All you really need to do is hit with both arms, back up, hit with both arms, back up, etc. etc. I don't really have any suggestions though (I can't think of any good way to make it harder), maybe add some more customization?
Anyway, great game.