Valve has announced that The Passing, the first game add-on for its cooperative zombie thriller, Left 4 Dead, will be released on April 22 for PC and Xbox 360.
The add-on brings the original Left 4 Dead Survivors down south for a meeting with the L4D2 cast, and will feature new single-player, multiplayer and co-operative gameplay.
The Passing also introduces a series of weekly game mode events dubbed “Mutations.” These week-long runs of new gameplay modes range from “Realism Versus” mode to “Chainsaw Massacre,” which gives all players chainsaws with an unlimited supply of gasoline. There are over 20 Mutations planned, each playable on all L4D2 Campaigns. Mutations will be exclusively available to owners of The Passing DLC.
In addition, The Passing offers a new co-operative challenge mode, support for infected bot play in Versus, a new “uncommon common” zombie class (the fallen survivor), melee weapon (golf club), and firearm (M-60).
The Passing will be priced 560 MS Points on Xbox 360 and free on the PC.