Left 4 Dead -- Crash Course

Crash Course delivers new single-player, multiplayer and co-operative gameplay, and bridges the gap between the end of the "No Mercy" campaign and the beginning of "Death Toll" in the original game.

While containing both Survival maps and a Co-operative Campaign, the primary goal of Crash Course is to deliver a complete Versus mode experience in just 30 minutes, resulting in a streamlined version of the game's existing Versus campaigns. A recharge timer for infected teammates has also been added, and item spawn behavior has changed for more balanced gameplay.