I have watched this demo and everytime he shoots, in slow (around 30% speed), imo there appears to be no aim assist, no aimbot, and he definately isnt walling because if so he would have noticed the people alot more. He spent more time running the opposite direction than anything. As for the deagle headshots, he never aims below the waist and takes his time with his shots. Example at around tick 17400 when Andy was rounding the corner, he was clearly able to be heard running and when Blaze shot he took 3 shots to kill him, the first hitting his shoulder, second hit the wall at the corner right above andy's shoulder and the third was in the head.

No Hacks, Just good sound awareness and takes time.