As you may recall, a few days ago Valve issued a challenge to Left 4 Dead 2 players: If 20,000 players beat the still-in-development “Cold Stream” campaign by this Sunday, then the Left 4 Dead 1 campign, “Dead Air,” would be released early. Consider that challenged owned, Valve. It didn’t take more than four hours for it be achieved either.
That means that now Left 4 Dead 2 players can expect the “Dead Air” campaign to hit soon, no later than July 22 Valve promises. Why not just release it now? Well, Valve is still working on putting in some final tweaks into the returning campaign. We’ll have more news for you is it comes.
[Source]