Hehe... That's pretty cool actually.
I noticed that he looked different from the "standard" head models, but I didn't really think much about it at the time.
I have also had quite a few random lock-ups while playing the game. It's a bit frustrating. Although I've had similar issues playing Halo2, so I suppose it could be my system. Although none of my other games do it.
Compared to a PC the graphics aren't anything special. But for a console, they're great.
I have experienced some frame-dropping, mostly in battles with lots of opponents. Nothing too terrible though.