Crash Course delivers new single-player, multiplayer and co-operative gameplay and bridges the storyline between the No Mercy and Death Toll campaigns in the original game. To celebrate, we are offering Left 4 Dead at 50% off for 3 days. Or share the fun - get the Left 4 Dead Four Pack and give the game to your friends.

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.