On April 22, 2010, Left 4 Dead 2 fans will finally get their chance to sample “The Passing,” which is the first DLC add-on for Valve’s popular zombie shoot-em-up. This campaign takes place immediately after the “Dead Center” campaign in a small town in rural Georgia. And yes, as previously reported, you will encounter the original survivors from Left 4 Dead. But wait folks, there’s more!

The DLC is free for all you lucky PC users and 560 Microsoft Points for the Xbox 360 crowd (grrrr).

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 are exclusively available to owners of “The Passing” DLC.

In addition, “The Passing” offers a new co-operative challenge mode of play, support for infected bot play in Versus, a new “uncommon common” zombie class (the fallen survivor), melee weapon (golf club), and firearm (M-60).

In celebration of the “The Passing,” you’ll have the opportunity to compete or play with Valve employees on Thursday, April 22, 2010. For the PC, go online between 11 am and 5 pm PDT and friend one of the following accounts:

For Xbox 360 users, sign on between 7 pm and 11 pm PDT and add one of the following to your friend’s list:

L4D2_DEV_1, L4D2_DEV_2, L4D2_DEV_3, L4D2_DEV_4, L4D2_DEV_5, L4D2_DEV_6, L4D2_DEV_7, L4D2_DEV8, L4D2_DEV_9, L4D2_DEV_10

Oh and if you’re a PS3 fanboy and you happen to link up with Gabe Newell, please be nice.

L4D2 DEV 1, L4D2 DEV 2, L4D2 DEV 3, L4D2 DEV 4, L4D2 DEV 5, L4D2 DEV 6, L4D2 DEV 7, L4D2 DEV 8, L4D2 DEV 9, L4D2 DEV 10

“The Passing” shuffles its way onto both the PC and Xbox 360 on April 22, 2010.

Source:  Left 4 Dead Blog