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 (40) - 92% of the 40 user reviews in the last 30 days are positive.
All Reviews:
Very Positive (2,978) - 94% of the 2,978 user reviews for this game are positive.
Release Date:
Dec 5, 2014

Sign in to add this item to your wishlist, follow it, or mark it as not interested

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 (179)

November 9

Lambda Wars Update November 9, 2018 (3.11a, rev. 6564)

Hey guys! Been a while.

We are getting closer to releasing a very important update with some other changes.

Right now we have an update ready with some fixes and balance changes which hopefully will change the gameplay for hardcore players :)

Here is the changelog:

Lambda Wars Update 09 November 2018 (3.11a)
  • Antlion population requirement removed
  • Shotgun unlock time increased from 20 to 45 seconds
  • AR2 unlock time increased from 20 to 90 seconds
  • Weapon upgrade price for Combine SG changed from 10/25 to 10/30
  • Rescaled AR2 and SG combine prices from 50/10 and 45/5 to 45/15 and 40/5
  • Manhack price increased from 10/0 to 10/3
  • Rescaled Power Generator generation frequency from 0.15 per 3 sec tick to 0.2 per 4 sec tick
  • Rebel Partisan health increased from 50 to 75
  • Rebel Marksman/Veteran (should I just rename it back to Veteran?) pop increased to 3
  • Population from Combine Elite and Rebel Flamer increased from 2 to 3
  • Metropolice and Metropolice SMG movement speeds were swapped (pistol runs faster now)
  • Added synth factory requirement for researching Strider upgrade
  • Barrels from barrel trap tower now cost 1 scrap
  • Reduced bonus damage from RPG and Flamethrower against building
  • Sniper attack speed slightly increased

    Frag grenade:
  • Grenade now doesn't cost anything to toss
  • Reduced cooldown from 120 to 40 seconds

  • Mortar no longer fires after death
  • Medic being able to heal globally
  • Dog being healed by Combine aid station
  • Stalker attack working in bursts instead of continuous attacks
  • Rollermine bleed effect
  • Dog & Hunter jump fix
  • Strider showing bleed effects
  • Dog having weird bleed effects and loop sounds

  • Now attempts to hit its enemy

  • Various changes for 90% of the maps. Mostly navigation and balance-wise though. Credit goes to Mr. Lazy.

  • New Veteran/Marksman unit icon

Hey, by the way.
I made a photo like 2 weeks ago. And since I used news for memes, I want you guys to meme this:

You may post these in the Lambda Wars artworks if you like! (or otherwise leave a comment with a link) You know, to maintain some fun around this section.

Have fun y'all!
11 comments Read more

August 23

Lambda Wars Community Survey - Summer 2018 Review

Thanks for participating in the community survey, we had a total of 82 responses. I've emailed back as many people as I can and I am working on compiling the short list of the best suggestions you sent us. In the meantime, here's some data.

What mode do you play the most?

What faction is the most powerful?

What type of game should Lambda Wars be?

What updates you guys like:

Thanks for participating in the survey, feel free to use the steam discussions to suggest more content and provide feedback.

- vin
17 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 :(

What Curators Say

12 Curators have reviewed this product. Click here to see them.
Customer reviews
High Volume of Reviews Detected:
Exclude  or  View Only
Review Type

Purchase Type


Date Range
To view reviews within a date range, please click and drag a selection on a graph above or click on a specific bar.

Show graph

Display As:
Review Beta NEW!
When enabled, will sort reviews by new Helpfulness score. Read more about it in the blog post.
Show graph
Hide graph
Review Helpfulness Beta Enabled
There are no more reviews that match the filters set above
Adjust the filters above to see other reviews
Loading reviews...