You are not logged in.
During the development, there's a few things we had to accept and among these is the fact that not everything is possible in a Left 4 Dead campaign. Because of this, there's a few problems we are aware of but can't fix or didn't had the time to fix before release. Here's a little list just so you guys know what's going on.
BEWARE, THIS LIST CONTAINS SPOILERS REVEALING PART OF WHAT HAPPENS DURING THE I HATE MOUNTAINS CAMPAIGN. YOU SHOULD NOT READ IT IF YOU DON'T WANT MOST OF THE ACTION SPOILED.
See the original post for a list of common things we can't fix: