Valve, creators of best-selling game franchises (such as Half-Life, Portal, Team Fortress, and Counter-Strike) and leading technologies (such as Steam and Source), today announced that Crash Course -- the second downloadable content (DLC) update for its co-operative zombie thriller, Left 4 Dead (L4D) -- will be made available worldwide on September 29 on Xbox 360 and PC.

Crash Course delivers new single-player, multiplayer and co-operative gameplay to both platforms, 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.