I watched the demo, I didn't see anything like cheating, He was clearly professional players and got skills with awp.. I didn't see him aiming at someone through the wall, and when he was aiming at the wall, it wasn't at the enemy and it was wallbang, as i saw also he was aiming at the places that the enemy mostly goes there.. and the last 2 kills he was using sounds, cuz there was an enemy hiding there and he shot his awp, so he heard him and killed him, the last thing is the screenshot, there was a guy behind the wall and its clear no wallhacks.