Wow. Blown away, man.
Such a solid game, and it's not your typical one-on-one structure either. Must have taken you a long time to put this together. One thing I will say is that in between stages, your dialogue (the little that's there) doesn't sound that great, and I'm not too keen on the letters you use there either. I'd like to see illustrations or something at that point... I mean, you don't need a huge story, but maybe put some style into those segments.
Little stuff, though. Awesome game overall.