wallhacks don't look like that demo he made.. They simply just spec'd him and recorded, then went and re-recorded the demo with mat_wireframe.
Its a great tool once you have a fps demo, to see how a hacker's crosshairs will line up a player when strafing around a wall, etc.
Unfortunately, there are alot of wall hacks out there.. some with wireframe walls, some with transparent walls... one that is plagueing the community, yet can never be VAC detected are custom model hacks. These will allow a player to see all models (friendlies and enemies) pretty much through anything. All walls remain the same, but you can see the player models through them. This cheat is very hard to detect since teams can use it wisely and not get caught. For instance, they can have a player "hang back" and spot enemies for teammates to kill. No one ever disputes the guy that goes 3-14. What stinks about it is that valve claims they will never do anything restricting a player from customizing their models (for obvious reasons).
Anyway, nice catch boys!