Good news for all Left 4 Dead 2 fans. The Dead Air Campaign from Left 4 Dead has been ported over to Left 4 Dead 2.
Valve released it recently on 22 July 2011 after more than 20,000 players beta tested and complete the Cold Stream Campaign.
I think I’ve been playing too much Team Fortress 2 until my L4D2 skill drop. Now I play like a noob. Haha. Need more practice. Check out this walkthrough video. Obviously not done by me.