Left 4 Dead 2 / L4D2 Gaming Lessons and Pro Gamer Training

Left 4 Dead (L4D) is a cooperative 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 went gold on November 13, 2008, and was released on November 18, 2008, in the United States; and on November 21, 2008, in Europe.

Set during the aftermath of an apocalyptic pandemic, the game pits its four protagonists—dubbed the "Survivors"—against hordes of the Infected, zombie-like aggressive mutants. There are four game modes: a single-player mode in which allied characters are controlled by AI; a four-player, co-op Campaign mode; an eight-player online versus mode; and a four-player Survival mode. In all modes, an AI, dubbed "The Director", controls level pacing and item spawns, in an attempt to create a dynamic experience and increase replay value.