The public beta for Cold Stream, a community-created campaign for Left 4 Dead 2, is available for free download from today.

Cold Stream takes place after The Parish campaign, but how the story progresses between them is unclear at this point. The beta focuses mostly on testing the gameplay, and after an hour or so of playing, it’s clear that there are bugs that need fixing. These range from simple things, like overly-bright lighting in parts and blocking volumes in weird places, to potentially game-breaking issues, like unclear directions and apparently impassable areas. But hey, that’s what betas are for.

Problems aside, the campaign features three stages, primarily channelling the survivors along a river. It creates some interesting new challenges, particularly in Versus mode, as the Infected can perch up on the high banks and pick off the survivors with relative safety. The characters’ dialogue is so far just taken from the rest of the game, but once new lines are included, the directions may become clearer.

Once it’s fully up and running, Cold Stream should be a welcome addition to the already generous campaign range being offered. If you want to try the new campaign out (and assuming you already own Left 4 Dead 2), it will automatically start downloading when you open Steam. Also coupled with the download is an improved Steam chat system, based on Skype.

Valve has also announced that the rest of the campaigns from the original Left 4 Dead will soon become available in the second game as well, joining No Mercy, which has been playable for some time.