I don't know how many people are still playing, but I had a blast with this DLC and played a good bit of it. There are two different modes; one is essentially a deathmatch mode (with zombies!) and the other is supposed to be essentially a 4P version of The Mercenaries, but you can shoot each other. The problem, which is what Demi is talking about, is that distinguished mentally-challenged fellows play it like deathmatch (you get score penalties for this, IIRC) for whatever stupid reason.
If you play with the right people, it's great though. I played with friends, and whenever some idiot would go and start fucking shit up in the survival mode, we'd just gang up on him and kill him over and over again (WHILE taking out zombies) until the guy would rage quit. That was always fun.
