I've checked the demo, it shows obvious wallhack..
At the second round you walk towards B, you don't look to your left or right to check if there is someone, why you say? Because you are focusing on the people at B. (At Killerftw) You can see that your crosshair is look towards the wall, where most of the people would aim to every corner to check for an enemy to bump up, that is because your eyes are on the target, and not on your crosshair. (Something very obvious with wallhackers.)
Goodluck.