The first game add-on for Left 4 Dead 2 brings the original Left 4 Dead Survivors down south for a meeting with the L4D2 cast, while delivering new single-player, multiplayer and co-operative gameplay.

Left 4 Dead 2 will be automatically updated with this free add-on. To celebrate this release, L4D2 and the 4-Pack will be 33% off until Monday.

About the update:

"The Passing" features 3 new maps, new weekly game modes (Mutations), a new "uncommon common" zombie class (the fallen survivor), melee weapon (golf club), firearm (M-60), support for infected bot play in Versus, 10 new achievements and more!