The new DLC prequels The Passing, and is playable from the vantage-point of our beloved survivors while battling southward. The Sacrifice not only furthers the previously laid-out plotline, but also brings forth a newly styled finale, with what Valve dubs "Sacrificial Gameplay" (mmm, sounds gruesome); Sacrificial Gameplay encourages gamers to decide who gives up their lives so that others may continue living in this infected, horrific setting.

Valve issued the following statement:

In The Sacrifice for Left 4 Dead 1 gamers receive the complete Sacrifice campaign with maps playable in Campaign, Versus, and Survival.

In The Sacrifice for Left 4 Dead 2 owners receive "The Sacrifice" campaign playable with the Left 4 Dead Survivors. In addition, those with Left 4 Dead 2 receive L4D's "No Mercy" campaign. Both campaigns are playable in Campaign, Versus, Survival, and Scavenge modes and both will feature the Left 4 Dead 2 Special Infected, items, and weapons. Yes, Zoey with a chainsaw!

Targeted for release on October 5th, "The Sacrifice" will be available for download on Xbox Live for 560 Microsoft Points and free to all PC gamers.