Left 4 Dead 2 "Swamp Fever" Hands-On ImpressionsS

Valve brought a playable "Swamp Fever," the second announced campaign for Left 4 Dead 2, to Comic-Con. In addition to showing a new environment in which to kill zombie hordes, it helps the game feel more like a proper sequel.

At E3, the campaign "The Parish" played a touch too much like the original Left 4 Dead, just with sunlight and four new character skins. Sure, there was the new special infected, the Charger, and melee weapons, but fans of the first were somewhat justified in questioning what the sequel really added.

But our hands-on with "Swamp Fever," which features the newest addition to the infected side, the Spitter, gave us a better impression of the just how Left 4 Dead 2 is mixing up the formula.

First, there's that Spitter, the lanky, pig-tailed, pot-bellied special infected class that can spew forth a damaging orange liquid. Like the Charger, her splash damage attack, which damages Survivors over time, breaks up clustered Survivors. Her venom sounds like a swarm of bees, looks like a pile of boiling magma and burns like acid. It's napalm-like, so wading through the pools of water in Swamp Fever doesn't offer protection against the burning attack. It put me (actually, Coach) out of commission fairly easily.

I partly blame my lack of vision—and my teammates, of course, as is my tradition when anything goes wrong in Left 4 Dead—obscured by a few Mud Men attacks. The new "uncommon common infected" might have been the ones responsible for getting mud in my eye, making it even harder to see my zombie attackers. Those Mud Men are tough to fend off, bearing a smaller profile to shoot at as they crawl on all fours.

Also crawling on all fours is the Hunter, obviously, who can pounce from underwater, benefiting from extra camouflage during this campaign.

Actually, all infected benefit from the swamps, as Survivors move slower while in swamps. Tactically, you'll definitely want to stay on dry land or man made platforms as much as possible. But you're going to have to get wet at some point.

Swamp Fever features at least two of the improved gauntlet scenarios. Players must call a ferry from across a river, without the option of having comfortable corners to back into. Another takes place inside a downed plane, forcing players to squeeze through an emergency exit door. The environment is tough to navigate, with our fight spreading out across the plane wing, inside the cabin, and in and around the murky waters.

We got to try out the new AK-47, which feels a lot like the assault rifle from the first. We didn't pick up the grenade launcher or the cricket bat, but our teammates did. The new ammo packs and adrenaline shots weren't in the build we played, so there's still a lot more to see.

Overall, the game is starting to feel like a more unique experience thanks to these additions, something hesitant Left 4 Dead 2 fans will probably welcome. We're happy to see the game get more gameplay set during nighttime. Combined with the foggy, natural environments, Swamp Fever adds a very creepy atmosphere to the more brightly lit episode, The Parish.

We'll be playing more of Left 4 Dead 2 at Comic-Con, going hands-on with the rest of Swamp Fever at a Microsoft event later tonight.