Originally Posted by identitycrisis
haha, how does the mp work? is it like 20 vs zombies, or does it limit to groups of 4 or something?
4 survivors. The Valve AI Director controls how many zombies attack you and when they attack you based on a lot of different real time variables. There are also trigger sequences such as setting off car alarms that will trigger hordes. The hordes usually consist of up to 40+ zombies, but can be more or less as well.
That's in co-op single player where you play with friends in the campaign.
Multiplayer is essentially 4 survivors vs regular zombies and 4 (I think) players that play as boss zombies such as the Hunter, Witch, Smoker, Boomer, and Tank.