Campaigns are storylines consisting of several maps.
- Alien Swarm Reactive Drop has ten official campaigns, though only 8 of them have Steam achievements associated with them (Bonus Missions and Deathmatch do not).
- Alien Swarm Source launched with a single official Campaign, Jacob's Rest.
- Alien Swarm 2K4 launched with two official campaigns Sigma and Ortega, and later added four community campaigns Phalanx, Upsilon, Telic, and Escape From Rhea.
|Campaigns • Characters • Enemies • Equipment • Promotions • Skills • Weapons|
Background • Challenges • Console • Difficulty • Experience • Server setup • Speed running • Steam achievements • Strategy