Left4Dead

Left 4 Dead is a co-operative, survival horror, first-person shooter video game. It was developed by Turtle Rock Studios, which was purchased by the Valve Corporation part-way into development. The game uses the Source engine, and is available for Windows and the Xbox 360. The game pits four Survivors of an apocalyptic pandemic against hordes of aggressive zombies. There are two game modes: a four-player, co-op Campaign mode, and an eight-player Versus mode. In both modes, an AI, dubbed "The Director", controls level pacing and item spawns, in an attempt to create a dynamic experience and increase replay value. The game went gold on November 13, 2008, and was released on November 18, 2008 in the United States; and on November 21, 2008, in Europe to coincide with the tenth anniversary of the release of Half-Life. A five-minute trailer was released on Halloween. A playable demo was made available on November 6 for pre-purchasers and on November 11 for the general public, and was closed on November 18, 2008. The demo contained the majority of the first two chapters in the "No Mercy" campaign, and was playable in both single and multi-player co-op. Left 4 Dead was well received with an aggregate score of 88% on Game Rankings and 89% on Metacritic upon its release, with praise given for its replay value, focus on cooperative play, and movie-like experience. As they have done with Team Fortress 2, Valve intends to support the game with downloadable content. Left4Dead in a few words Left 4 Dead is a first-person shooter but makes use of the third-person perspective during certain events or player actions. In Campaign and Single-player mode, the player takes control of one of the Survivors; if four human players are not available, then the remaining Survivors are AI-controlled bots. They play through the levels fighting off the "Infected"—living humans who have been infected with a mutagenic, rabies-like virus to which the Survivors are immune. Survivor characters There are four playable human characters in the game: Francis (voiced by Vince Valenzuela), a tattoo-covered biker; Zoey (voiced by Jen Taylor), a college student and horror movie enthusiast; Louis (voiced by Earl Alexander), a Junior Systems Analyst in his company's IT department; and Bill (voiced by Jim French), a former Green Beret and a Vietnam veteran. Infected characters The "Infected" (voiced by experimental musician, Mike Patton) are the Survivors' foes in Left 4 Dead, and they appear to be partly inspired by the infected from several modern films, including 28 Days Later. An important distinction is that The Infected are not traditional undead zombies, but rather living humans infected with a rabies-like pathogen. AI and the Director The artificial intelligence of Left 4 Dead features a dynamic system for game dramatics, pacing, and difficulty called "The Director." Instead of fixed spawn points for enemies, the Director places enemies and items in varying positions and quantities based upon each player's current situation, status, skill and location, creating a new experience for each play through. The Director also creates mood and tension with emotional cues, such as visual effects, dynamic music, and character communication. Valve has termed this dynamic set-up "procedural narrative."