A top-down bug hunt with squad tactics
Alien Swarm: Reactive Drop is a free co-operative top-down shooter built around hunting aliens with a team. You play from a top-down perspective, which keeps the whole map readable and lets you coordinate movement, cover, and firing lines with the rest of your squad. The game extends Alien Swarm with more maps, more aliens, more game modes, and more guns, so there is a lot of content to work through once you are comfortable with the basics. It also includes new aliens such as HL2 antlion guards, plus new weapons like the Bulldog, Devastator, and Combat Rifle, with more to come.
Playing together with your group
Tactical co-op supports up to 8 players, so a larger Discord group can jump into the same mission and split roles across the squad. The top-down view makes it easy to call out positions, mark threats, and coordinate pushes without needing a shared map overlay. Beyond the co-op campaigns, there are Challenges, which are modifications of the game in the same spirit as Mutations in Left 4 Dead 2, giving your group a fresh twist on a familiar map. If your group prefers competing against each other instead of aliens, PvP modes include Deathmatch, Gun Game, Instagib, and Team Deathmatch. Leaderboards let you compare mission completion times with friends, and improved spectating shows hacking minigames and mouse movements in real time, which is useful when someone is watching a run rather than playing it.
Before you start
Singleplayer is available with improved bots on all official maps, so you can learn a map solo before bringing the group in. Steam Workshop support opens up community maps and challenges, and the game is moddable, which means your group can keep finding new content over time. There are over 100 Steam achievements to work through alongside the main missions. The game carries both top-down and first-person tags, so check which perspective a given mode uses before you queue up.