There's another free FPS out there called Warrock, which I'm sure most of you have at least heard of, if not played. It's a very good game, with a good premise, that the company (k2) let completely go to hell. They dropped a lot of their programmers, who in turn, started their own 'companies' making hacks. That game is the most hack ridden game in existence since Diablo 1. People flying around, coming out of the floor, shooting through walls, or launching 300 grenades at once.
This isn't some new issue either, and that's why it's so terrible. They release a patch, and theres already hacks out for it the next day. Some have speculated k2 may actually themselves have a hand in hack creation.
I will never play that game again. I suggest you don't either. I don't get mad at video games, with the one exception of hackers. I hate hackers with a passion few can understand (game hackers, specifically).