Lovely!
I've watched this literally five times since discovering it this afternoon. I can't get it out of my head. I see it as a very gripping metaphor for the choice between accepting society the way it is (turning a blind eye to flaws and injustices) or realizing the evil in the world and speaking out against the crowd.
First and most obviously, the graphics and animation are outstanding. The music is reminiscent of that used in films about the Holocaust, Hiroshima and the like. I don't know whether that was intentional but it certainly adds to the effect.
The moment where he ALMOST smiles is the most wrenching part for me--it's like trying to go from consciousness of the flaws of humanity back to forced ignorance, simply because it hurts less that way. Seeing the blood is what reminds him that he can no longer pretend the world is happy and cheerful. It's ugly, pure and simple.
I may be completely offbase here, but I believe the seemingly random orgy is a clever reference to the pointless, pleasurable activities modern people use to quell their consciences. Turn on the television or computer (ha!) and you no longer have to think for yourself. It's all about what makes you happy, rather than what's right.
But then I may be reading too much into this whole thing. Either way, thumbs up.