Whoa! Whoooaaaa! Damn! This is awesome, I don't even remember seeing this for some reason (with the exception of your avatar).
The only thing I'd suggest is either changing or allowing the option to change the mouse sensitivity. The mouse was WAY to sensitive, and I found it difficult to navigate and look around without become seasick. Also, the "footstep" swaying effect is impressive, but unecessary. It reminds me of one of those later Doom games (or maybe Quake or something) where your vision would sway back and forth in conjunction with your stride, and I thought, "God, this is annoying".