Valve has announced the development of the first expansion dedicated all'FPS horrific Left 4 Dead 2 called "The Passing". The content will be available on the Marketplace in early 2010 and will add a campaign in which the protagonists of this second installment in the series will meet with those of the original title, were not disclosed more details about this. The expansion will also include unpublished arenas for survival mode, Versus and Scavenge, new zombies, other weapons and a new cooperative mode.