Lambda Wars is a free standalone multiplayer Source Engine modification set in the Half-Life 2 universe that brings the war between mankind and their brutal Combine overlords to a traditional real-time strategy (RTS) setting.
Recent Reviews:
Very Positive (65) - 95% of the 65 user reviews in the last 30 days are positive.
All Reviews:
Overwhelmingly Positive (2,471) - 95% of the 2,471 user reviews for this game are positive.
Release Date:
Dec 5, 2014

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Community-Made Mod

This is a free community-made modification for Alien Swarm set in the Half-Life 2 universe.

Click here to learn more about mods on Steam.

Install Lambda Wars Beta

Free Alien Swarm Mod


Recent updates View all (150)

November 17

LW News! (Week 6)

Hello Strategists!

Man, another slow school (or work) week for us all, right?
Well, for those of you celebrating, Happy Early Thanksgiving! And those of you that just want this year to be finished, Happy HallowThanksMas!

Now, onto business. Sadly, the development crops haven't dropped ripened fruit quite yet, but we have our oh-so beloved Dr. Mad looking at units, and deciding what entirely needs balancing and such.

Luckily for us, our beloved slave Mr. Darkness is finishing up his real life stuff (Gross, I know) and will be back to hs "90 Hours a Week and Loving It".

P.S. - Please stop asking about New Races, PLEASE. We've said 5 too many times that there are NO plans to add any new races to the game. Thank you.

P.P.S - First to tell me which movie I referenced with the line "90 Hours a Week and Loving It" will get bonus points.
11 comments Read more

November 12

Engine errors?

Hey guys.

Recently I heard a number of you peeps are getting the following:
Engine Error - "Could not load library client"

If this seems familiar to any of you, please make sure you're:

  • Not running Windows XP. It's no longer supported. Vista users crash a lot, according to our minidumps.
  • Launching a fresh download of the game OR have just recently updated, became unable to play while previously were able to launch the game before.
  • Didn't fiddle with the game library on your own without knowing exactly what you're doing or haven't followed a developer's instructions. The game library is located under Steam/steamapps/common/Lambda Wars

Keep in mind that the game launches alright for us devs and majority of players, so it must be something to do with your system specs or the file system. This is something I'm trying to look into right now.

Please leave your reports either in the comment section, discussions or contact me through either Discord or VK.
10 comments Read more

About This Game

Lambda Wars is a free multiplayer Source Engine modification for Alien Swarm set in the Half-Life 2 universe that brings the war between mankind and their brutal Combine overlords to a traditional real-time strategy (RTS) setting. Lead the uprising as a commander of the Resistance or crush the rebellion as an overlord of the Combine, with both factions featuring a full host of units, abilities, buildings, research and defenses. Lambda Wars features full-fledged RTS gameplay and a robust RTS interface and is focused on multiplayer but strategic AI opponents and dedicated singleplayer missions are also included.


  • Classic real-time strategy (RTS) gameplay in the Half-Life 2 world
  • Multiplayer support and game lobby including spectator mode
  • Wide variety of maps for up to 8 human or AI players
  • Play as either Combine or Resistance (and also Antlions in Sandbox mode)
  • Full unit tech tree that allows you to command everything from Manhacks to Striders
  • Full-fledged RTS interface and HUD with everything from minimap and fog of war to unit and production building groups
  • Build production and research facilities to requisition better units and unlock abilities and upgrades
  • Defensive structures, turrets and mines help defend your headquarters and vital resource points
  • Multiple game modes
  • Singleplayer missions, tutorial map and offline AI skirmish mode

System Requirements

    • OS: Windows 7
    • Processor: Dual core from Intel or AMD at 2.8 GHz / Quad-Core Intel at 1.33 GHz
    • Memory: 1 GB RAM
    • Graphics: Intel HD Graphics, nVidia Geforce 8600GT, AMD Radeon HD2600 or better
    • DirectX: Version 9.0c
    • Storage: 4 GB available space
    • Sound Card: DirectX 9.0c compatible sound card
    • Additional Notes: These are the minimum requirements to be able to run on lowest settings
    • Memory: 3 GB RAM
    • Additional Notes: Being able to go easy on us devs for all the bugs and glitches :(
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