If you boot up Left 4 Dead 2 today you'll notice a new addition to the campaign list. The modder made map, Cold Stream , has been added to the line-up as a beta campaign. It looks a lot more polished than you might expect from a beta map, but Valve expect players to find a few bugs. To help people report problems, they've extended the in-game bug reporting feature, and asked that fans post feedback on the Cold Stream Steam forums . For more information, check out the Left 4 Dead 2 blog .