In versus mode, eight players are split into two teams of four and put in control of the survivors and infected. In each string of maps, of which there are four total, there are subsections. Each subsection starts off with the survivors in a safe room where they can stock up on ammunition, weapons, and health packs. They then need to sprint out a door into the open and make their way to the safe room at the end of the subsection. In the campaign mode, you just continue through until you reach the end of the map string. In versus, players play each subsection twice on both sides. So if you play through the first time on the survivor side, you'll play through next as infected. After each round the survivor team is scored based on their distance travelled across the subsection, their remaining health, and the score is multiplied by a difficulty rating and the number of team members left. This is added up across each subsection and totaled at the end of the map string to determine a winner. Then it's back to the waiting lobby where both teams can mercilessly insult or congratulate each other.

For the survivors, the action is fast and frantic. You don't spend a lot of time aiming in the game. In fact, with all the weapons but the sniper rifle, you only shoot from the hip. There's no aim-down-the-sights ability. It seems the best strategy with pistols, shotguns, submachine guns, assault rifles, and auto shotguns is to level your reticule at the enemies' shoulders and hope for headshots, which blows the infected craniums to pieces. You can still do plenty of damage without headshots, though, as you'll be able to blast away appendages or perform a melee swipe to back enemies up, momentarily stunning and priming them for a quick spray sweep of your weapon. You'll also need to keep an eye on where teammates are, something made easy as they're highlighted in an outline if they're behind objects so you'll never stay separated for long. Teammates can heal each other with health packs, revive each other, and give pills back and forth, something you'll definitely need to do against a good squad of infected.