Alien Swarm: Reactive Drop extends Alien Swarm, bringing more of everything: maps, aliens, game modes, guns... And most importantly Steam Workshop support.
- Tactical, 4 player or 8 player co-op action game with a top-down perspective
- Steam Workshop support for community maps and challenges
- New co-operative campaigns
- Challenges: Modifications of the game, just like Mutations in Left 4 Dead 2
- PvP: Deathmatch, Gun Game, Instagib, and Team Deathmatch
- Single-player: Play with improved bots on all our official maps
- New Aliens: HL2 antlion guards and more
- New Weapons: Desert Eagle, Devastator, Combat Rifle and more
- Over 100 Steam achievements