ABOUT THIS GAME
Alien Swarm: Reactive Drop extends Alien Swarm, bringing more of everything: maps, aliens, game modes, guns... And most importantly Steam Workshop support.
Quote:[i]Tactical co-op for up to 8 players 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
Singleplayer: Play with improved bots on all our official maps
New Aliens: HL2 antlion guards and more
New Weapons: Desert Eagle, Devastator, and Combat Rifle, with more to come
Over 100 Steam achievements
Leaderboards: compete with your friends for the fastest mission completion
Improved spectating: see hacking minigames and mouse movements in real time[/i