Rock Paper Shotgun writes
"So far you'll have seen details of two of Left 4 Dead's four campaigns, No Mercy and Blood Harvest. Today we have a world exclusive first look at a third campaign, Dead Air. What follows is a detailed photo "essay" (using that term loosely) of our experience in the campaign - reveling and revealing details from its quiet beginnings to its climactic conclusion (i.e. SPOILERZ). It's a terrifying journey through a town complex to reach the airport and escape the city. It starts in a shattered commercial greenhouse with a plane going overhead. The team decides to set out and try to get picked up by the military craft…"