Wall hacks: None
No recoil: Yes, this can be easily picked up when he buys an M4 the first time

Im going to go with aim assist though, for the following reasons.

i watched all the way up to tick 30k, EVERY single one of his head shots was made with his cursor off the right side of the persons head, he never directly gets a head shot while aiming at there heads. This can be noticed more specifically on his head shots streak starting at tic 8k. Slow the demo down to 15% starting at 8k.