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 (81) - 95% of the 81 user reviews in the last 30 days are positive.
All Reviews:
Overwhelmingly Positive (2,602) - 95% of the 2,602 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 (156)

January 12

Something Dire.

[T R A N S M I S S I O N - S T A R T]

Commanders, quick, I need you to get to this transmission as quick as you can!

We are have some amazing news! But, you must keep this a secret. If any of this information gets out, it could mean the end of us entirely! Rebels, Combine, take great care in keeping this information away from ANY thing that may be a spy.

[T R A N S M I S S I O N - E N D]
30 comments Read more

December 31, 2017

Happy New Year!

Hey they, Commanders!

Phew, been a couple of weeks since the last news post, innit?

Well, we at the Vortal Storm team thought that it'd be nice to give you lovely people an update before going on a bit of a hiatus from posting any info (hence the 2 lovely new maps you received) in our News.

Everyone here was hard at work, and I want to give them all thanks for doing the wonderful job they do. Give them some love in the comments below, show us your LW Pride!

Now, off of that, there isn't any news. We've been enjoying our Holidays, and I hope you all have too. I don't foresee much content being released between now and next year, so as they say in America, "Happy New Years!"


P.S. Post was written on 12/31/2017, 7:12 PM Central time.
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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