Left 4 Dead

Left 4 Dead, a cooperative first-person shooter arcade-style video game, was developed by Turtle Rock Studios, which was acquired by Valve Corporation during its development. The game utilizes Valve's proprietary Source engine and is available for Microsoft Windows. Set in the aftermath of an apocalyptic pandemic, the game features four protagonists, known as the "Survivors," who battle hordes of the infected. Left 4 Dead offers four game modes, including a single-player mode with AI-controlled allied characters, a four-player co-op campaign mode, an eight-player online versus mode, and a four-player survival mode. In campaign mode, players control one of the survivors and can be AI-controlled bots if four human players are not available. The game is a first-person shooter in which players fight off the infected, who are living humans infected with a rabies-like virus that causes psychosis. The survivors are carriers of the disease and do not exhibit any symptoms.