Campaigns

Campaigns (or movies) are storylines consisting of several chapters (levels, maps). At launch, the game will include four campaigns, developed by Valve Software. They are, in chronological order:
 * 1) No Mercy,  focused on moving towards a Hospital for evacuation.
 * 2) Death Toll, based in a murky countryside.
 * 3) Dead Air, taking place on rooftops and inside an airport and a finale taking place on a runway.
 * 4) Blood Harvest, taking place in a countryside and farm.