Co-operative top-down shooter game available for free. An epic bug hunt featuring a unique blend of co-op play and squad-level tactics.
Recent Reviews:
Overwhelmingly Positive - 98% of the 115 user reviews in the last 30 days are positive.
All Reviews:
Very Positive (7,865) - 93% of the 7,865 user reviews for this game are positive.
Release Date:
Apr 20, 2017

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Play Alien Swarm: Reactive Drop


Recent updates View all (28)

November 9, 2018

Alien Swarm: Reactive Drop Update - November 10, 2018

An update to Alien Swarm: Reactive Drop has been released. The update will be applied automatically when you restart Steam. The major changes include:
  • Added Vietnamese translation for game UI by Nguyễn Tuấn Long
  • Added ability for each map to have its own background image for the loading screen.
  • Fixed white screen crash
  • Added new ConVars, VScript function, bug fixes

  • Add rd_sentry_refilled_by_dismantling cvar. If set to 1 marine will refill sentry ammo by dismantling it.
  • Fix bot frags are not counted for co-op missions. This caused ammo to not spawn from aliens in challenges that used the rd_spawn_ammo cvar
  • Fix white screen crash
  • Show yellow icon when player is speaking in Player List window. Also added rd_speaking_r, rd_speaking_g, rd_speaking_b ConVars to allow players to set their own color for speaker icon
  • Add rd_ray_trace_distance convar. Can be modified by challenges or maps(using Convars.SetValue() vscript) to increase the distance which can be targeted using grenade launcher.
  • Add VScript Function to spawn fire StartFire(). StartFire( Vector position, float duration, int flags ). Returns a handle to the created env_fire entity.
  • Add ConVar rd_biomass_ignite_from_flares(thanks to element109)
  • Add rd_auto_kick_low_level_player for challenges ASBI, TIER 1 and 2
  • Fix difficulty in ASBI is lowered for 3 or less marines. asw_adjust_difficulty_by_number_of_marines 0 was applied after the mission start but difficulty adjustment happens before this. This cvar was moved from
    challenge_asbi.nut to asbi.txt
  • Add rd_auto_kick_high_ping_player convar. If not zero the value will be compared to players ping and player is kicked if the ping is higher than the value.(thanks to element109)
  • Add ability for each map to have its own background image for the loading screen. The window's background image which is shown during map load can now be customized to show a unique image per each map. Added rd_loading_image_per_map cvar which can be used to turn this feature off.
    By default it is set to 1 which means the feature is enabled. This works for all maps, including community maps. Example of files required for the custom loading image to work(for rd-til4area9800.bsp map):
    Files with "_wide" suffix are meant for 16x9 aspect ratio resolutions.
    Files without suffix are meant for 4x3 aspect ratio resolutions.
    If custom material is missing a default material is used.
  • Fix uber drones are smaller when spawned from spawners. Uber drones default to 1.3 in size of regular drone. asw_spawner, alien selection and vscript code can change the size of asw_drone_uber by setting the Size Scale parameter. It is no longer required for asw_spawner to manually set uber drone's Size Scale to 1.3.
  • Add Vietnamese translation for game UI by Nguyễn Tuấn Long
  • Add antlion guard NPCs to the asw_clearhouse
  • Add rd_chatwipe cvar, set it to 0 to prevent chat wiping
  • Fix crash on connect introduced by custom loading image feature
  • Prevent inserting blank page to chat on mission restart if rd_chatwipe set to 0
  • Prevent camera rotation when not in game(thanks to element109)
  • Fix tech marine requirement is not disabled after hack on ocs2landingbay7
  • Fix skybox blinking black at start of bonus_mission2

Known issues

rd_chatwipe 0 can lead to chat being invisible after map just loaded, only happens once at first game start. This happens randomly. We are investigating this issue. If you have additional details on this issue, provide them in the feedback section of our discussions.

A default background loading image is shown when joining lobby for the first time.
25 comments Read more

July 25, 2018

Alien Swarm: Reactive Drop Update - July 25, 2018

An update to Alien Swarm: Reactive Drop has been released. The update will be applied automatically when you restart Steam. The major changes include:
  • Difficulty no longer increases for 5+ marines. Thanks to everyone who left their feedback regarding this feature.
  • Voice mute buttons. Players are now able to mute separate players using the Player List window(F9)
  • To improve user experience when browsing for public games players with in-game level below 30 and no promotions will not see games with a challenge enabled or difficulty harder than Hard.
  • [Modding]VScript access to info_node positions, new cvars
  • Miscellaneous fixes

  • Added rm_prespawn_num_biomass cvar. It can be used in user challenges to randomly create biomass around a map. Requires rd_prespawn_scale to be set to 1 or higher.
  • Updated description of rm_prespawn_num_* cvars
  • Set rd_increase_difficulty_by_number_of_marines to be 0 by default. Game difficulty will not be increased for 5+ players
  • Add mute button to player list window(F9). Thanks to element109 for the initial pull request.
  • Added VScript Functions to Get info_node Data.
    • InfoNodes.GetNumNodes() //Returns the amount of info_nodes in the network array
    • InfoNodes.GetNodeOrigin( int nodeID ) //Returns the origin of the node
    • InfoNodes.GetNodePosition( int nodeID, int hull ) //Returns the hull specific origin of the node
    • InfoNodes.GetNodeType( int nodeID ) //Returns the type of node
  • Add rd_drone_uber_knockdown cvar. Set to 1 to make uber drones knock down marines like shieldbugs do. Also added related cvars rd_drone_uber_knockdown_force and rd_drone_uber_knockdown_lift
  • Make asw_trigger_fall, trigger_hurt and env_laser kill marines even if reviving is enabled
  • Display number of incapacitations in player list window. If reviving is enabled F9 window(player list) will now display the number of times marine was incapacitated during current mission.
  • Fix marine is deleted after asw_suicide. This bugged out challenges with reviving enabled
  • Grey out difficulties above Hard and challenges for players below 30 level in Find Public Games window
  • Disable blinking light on area9800PP1 map to improve frame rate
  • Fix help hint is displayed permanently during bonus mission 1
  • Fix aliens getting stuck in huge yellow door on lan3_maintenance
  • Fix alien getting stuck inside wall on LandingBay_01
  • Fix uber drones getting stuck in door frames and windows
  • Add rd_auto_kick_low_level_player. Server auto kick players below level 30 from challenges which have this cvar set to 1. This cvar is meant for players who use dedicated server browser to join games, since Public Games window already restricts filters to max Hard difficulty and challenge being disabled
25 comments Read more

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.

  • 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

System Requirements

    • OS: Windows® XP or above
    • Processor: Pentium 4 3.0GHz
    • Memory: 2 GB RAM
    • Graphics: DirectX 9 compatible video card with 128 MB, Shader model 2.0. ATI X800, NVidia 6600 or better
    • DirectX: Version 9.0
    • Storage: 4 GB available space
    • Sound Card: DirectX 9.0c compatible sound card
    • OS: Windows® XP or above
    • Processor: Intel core 2 duo 2.4GHz
    • Memory: 4 GB RAM
    • Graphics: DirectX 9 compatible video card with 128 MB, Shader model 2.0. ATI X800, NVidia 6600 or better
    • DirectX: Version 9.0c
    • Network: Broadband Internet connection
    • Storage: 6 GB available space
    • Sound Card: DirectX 9.0c compatible sound card

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