The Passing

"The Passing will become the most important campaign in the Left 4 Dead story, as all the Survivors are being called together in one campaign."

- Doug Lombardi The Passing is an upcoming DLC for Left 4 Dead 2 which includes a new campaign and "a new co-operative challenge mode of play." Including new weapons, one melee and one firearm, it also introduces new Uncommon Infected. The Passing will take place between Dead Center and Dark Carnival, in a rural town in Georgia. It will also feature a meet-up between the Left 4 Dead 2 Survivors and the original Survivors, however, the original Survivors will not be playable and will definitely appear in the campaign's third chapter (and possibly others) helping Coach, Nick, Rochelle, and Ellis. The campaign will be playable in all the game modes, including the soon-to-be released one. Valve hasn't announced pricing details yet, but the release date is slated for late March for both the PC and Xbox 360 versions.

A programmer at Valve has stated that 16 player Versus will not be a reality, though he did hint at 8 player co-op as a possibility. There might also be a new game play mode, a co-op challenge mode.