Left 4 DeadLeft 4 Dead is a survival action game from Valve that blends the social entertainment experience of multiplayer games such as Counter-Strike and Team Fortress with the dramatic narrative experience made popular in single-player action game classics such as the Half-Life series of games.Set in the immediate aftermath of the long-awaited zombie apocalypse L4Ds single-player and co-op game modes are played out across four sprawling Movies set in a variety of urban and rural environments. Each Movie has an over-riding team objective is comprised of five large maps and may be played by 1 to 4 human players. New technology dubbed the AI Director is used to procedurally generate a different experience each time the game is played. Just as in Hollywood films the Director calls for new monsters sounds and action as it tailors the gameplay experience based upon the teams performance. In Left 4 Deads Vs. Mode players may play as a Survivor or as one of four types of Boss Infected. Each of the Boss Infected possesses an exceptional mutant ability - such as a 50-foot tongue lasso (Smoker) or a giant belly full of explosive methane gas (Boomer) - instead of traditional firearms.Left 4 Dead Survival PackThe Left 4 Dead Survival Pack is a collection of new content for 2008s Multiplayer Game of the Year. Headlining the pack is the new 1 to 4 person game mode Survival that challenges players and teams to survive unremitting swarms of zombies on over 10 maps. Rounds are scored by length of survival and times will be uploaded to leader boards. Also included in the Survival Pack are two additional Versus campaigns. Each campaign features 5 maps for additional play of the four-on-four multiplayer game that allows players to compete as Boss Zombies versus the Human Survivors.