Left 4 Dead (L4D) is a new action title from Valve creators of the Counter-Strike & Half-Life games that promises to redefine the co-operative genre as those titles did for multiplayer & single player action games Set in a modern day survival-horror universe the co-operative gameplay of L4D casts four " Survivors" in an epic struggle against hordes of swarming zombies & terrifying " Boss Infected" mutants The Survivor Co-op Game Mode is played out across four sprawling campaigns set in urban & rural environments Each campaign has an over-riding team objective & is comprised of five large maps The campaigns link together to tell the story of the Survivor&s escape to safety The team of four Survivors may be comprised of 1 to 4 human players allowing for single player & multiplayer co-op games Next generation AI technology powers all non-player Survivor & zombie characters This is facilitated by the AI Director a pool of systems used to procedurally generate a unique experience by monitoring the players& experiences & tailoring the pacing & difficulty of action for each game This makes for a different experience each time the game is played In Left 4 Dead&s 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 (Boome)
- instead of traditional firearms