As Valve promised, those who partake in zombie slaughter wholesale on Steam in Left 4 Dead 2 may now access an updated version of the original Left 4 Dead campaign, Dead Air. Beta access to Dead Air was promised as an incentive to the community for playing through the Cold Stream campaign (also in beta) and unlocking the subsequent completion achievement, Stream Crosser.

In a post on the Left 4 Dead blog, Valve reveals that the fourth and fifth maps in the Dead Air campaign have been changed a bit and that the developer "tried something new" when it came to the Scavenge map. The full Cold Stream DLC is currently slated to launch this summer on both Xbox 360 and PC.

This article was originally published on Joystiq.

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