Thanos is a bad bad man...er...I mean...Deviant. That's what his race is, I think. But he's got a different gene or something...I don't know. It's hard to decipher nerd-speak on that level.
The face that turned around after the first portion of credits, though, was unmistakabely correct. Proof:
I feel like one with my inner dork for knowing that. Maybe I should go get some graphic novels...oh wait, that's right, those things are expensive!