Deezay
All Star
Valve has been play-testing the Cold Stream downloadable content for Left 4 Dead 2 for over a year now. They just realized how ridiculously excessive that is and plan to release Stream through Xbox Live on July 24th.
Cold Stream is an all-new campaign created by Matthew Lourdelet, who was also responsible for "2 Evil Eyes" custom map. Stream takes the survivors through a wooded area. The campaign has been available on PC and Mac since March 2011. Players on those platforms have helped root out many bugs, so 360 players should have relatively smooth experiences with the content.
The downloadable content pack also includes three other campaigns: "Blood Harvest," "Crash Course," and "Dead Air." These are campaigns that shipped with the original L4D. Valve previously released the L4D campaign "No Mercy" for free as well, so an Xbox 360 L4D2 player will essentially have access to all the content from the first game. No word on how much players will need to fork over for such a hefty batch of DLC.
Cold Stream's release on the 360 will be accompanied by a new update for the game. This update will allow players to use mutations - modifiers to the game mechanics - at all times. You can create or join matches with Taannkk!, Gib Fest, and other mutations.
Valve is teasing some other "surprises and details." Maybe Cold Stream will be accompanied by even more free content? They'll announce this mystery information in the coming weeks.