When I play TF2 in 2D, I guess it's far enough away from reality that I don't try to understand what I'm seeing. When I play it in the Rift, I see a bunch of stuff that isn't quite right. I don't think it's the uncanny valley, because the game is still a cartoon. I really can't explain it any better than the author: after I play for a while, I need a nap.