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.
User reviews:
Very Positive (67 reviews) - 94% of the 67 user reviews in the last 30 days are positive.
Overwhelmingly Positive (2,156 reviews) - 95% of the 2,156 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 (118)

June 26

Lambda Wars June 26th Update - Version 3.07a

Lambda Wars Update 26 June 2017 (3.07a)
Game modes:

  • Work-in-Progress game mode "Squad Wars". This game mode is far from done, so don't expect it to be exceptionally finished, playable and balanced. Also, IT DOES NOT SUPPORT CPU!!!

Character Units:
  • "Chars" - units specifically for "Squad Wars" game mode. They have unique abilities, attributes and stats.

  • Explosive bolt now requires a munition depot.
  • "Fire" attribute now deals more damage against "creature" attribute (all non-human units, except synths and mechanical units).
  • Floor Turrets no longer require population. Previously they required 2 population.
  • Floor turret damage increased from 6 to 8.
  • Combine Elites now require both AR2 and Shotgun to be used.
  • Damage taken by units inside bunker was reduced even more now.

  • hlw_outland and hlw_waste - added manned turrets and floor turrets as early defenses. They become owned by the player that captures the closest control point.
  • sw_woodland, map hlw_woodland, but made for Squad Wars.

  • Improved veteran steady positioning.
  • Shield Generator can now be destroyed if it's unpowered.
  • Annihilation: No longer require useless structures like billets and energy cells to be destroyed. Only buildings that can produce units are required to be destroyed. The rest can be ignored.

Chars (Squad Wars):
  • Commando - Can shoot while running and tosses grenades. Can switch between a shotgun or an AR2. Very slightly reduced movement speed. 1000 HP. ASSAULT unit.
  • Elite - Equipped with an AR2. Can shoot energy balls that may harm his team. Deals increased damage. Slightly reduced movement speed. 800 HP. DPS unit.
  • Mechanic - Equipped with a pistol. Can produce manhacks, place floor turrets, set mines and place automatically constructed aid stations. 900 HP. SUPPORT unit.
  • Riot Tank (WIP) - Equipped with a stunstick. Can switch to SMG1. Can make cover spot for his allies to use. Is fast with his stunstick out and slow and more vulnerable with SMG1. TANK unit.
  • Scanner - Equipped with an SMG. Has abilities to deploy scanners and scan an area in the map for 15 seconds, as well as reveal invisible units. SCOUT unit.
  • Scout (WIP) - Equipped with an SMG. Can go invisible and stab enemies (doesn't work yet). Large view distance. Fast speed. 900 HP. SCOUT unit.
  • Flamer - Equipped with a flamethrower. Can toss smoke grenades. Slow speed. Short view distance. 1200 HP. TANK unit.
  • Veteran - Equipped with a crossbow. Can shoot explosive bolts. Has 800 HP. DPS unit.
  • RPG - Equipped with an RPG. Has slightly reduced speed. Can toss stink bombs. Deals more damage against bosses. 1000 HP. TANK unit.
  • Engineer - Equipped with a shotgun. Builds turrets, barrel trap towers and barricades. 900 HP. SUPPORT unit.
  • Medic - Equipped with an SMG. Can heal allies with his abilities. 1100 HP. MEDIC unit.
  • Assault (WIP) - Can shoot while running and tosses grenades. Has 1000 HP. ASSAULT unit.

  • Units no longer make pain sounds if they don't take damage (e.g. stink bomb).
  • More team colors - you now have 13 team colors to choose from.
  • Veteran renamed to Support Marksman.
  • "They Will Never Make A Stalker Out Of Me!" achievement was now fixed.

12 comments Read more

June 17

Status Update 15 - We're back baby!

Hey Commander!

A LOT has happened in the past few weeks. For example, Mr. Darkness has been to White Nights Business Conference for Game Development, which has been a positive experience for him, and will be in time for us too. I have concentrated on staying in the background and working on some other, exciting things that will help Vortal Storm reach a new level. More on that in a bit, though, let's start with what we always do..!

Community Update

Unfortunately, due to the absence of a lot of VS Staff Members, the community took a bit of a dive again. I hope that this picks up sometime soon, I will be speaking to several other folks on hosting some games and streaming them, but I cannot promise anything right now.

Development Update

As we have surpassed the half-year mark of 2017 already, we have set to thinking after White Nights. Lambda Wars is great, as we all realise, and will never be put under payment (as some people feared). It will remain a free mod from now until the end of times.

However, the future of Lambda Wars is discussed in the next segment.

So what hell is goin' on 'ere?!?!

Allow me to start at the beginning. Darkness did his part for Vortal Storm by attending a business convention in Russia which has shown to be very serious in its development. Giving both Darkness, and myself in turn some food for thought, we have come to a few conclusions.

Lambda Wars, while great, will not be Vortal Storm's one-stop-shopper. As we realised, it is only the beginning. Darkness and I speak of our next project a lot, which will feature Unreal- or Unity Engine. However, exactly what it will be is unknown as of yet.

We have, in collaboration with the above, decided to step up the serious vibe to the upstart that is Vortal Storm. Rather than just a bunch of collectives to one goal, we will now be attempting to grow, and hopefully - one day - establish ourselves as a company, and even have an office somewhere. (One can dream, right?)

And continuing on the 'serious vibe', there have been changes in staffing as well. As you may have noticed, some of the developers have been removed off their rank in order to restructure some.

And... As it stands, I will take official distance from my previous task as Community Manager. I will make way for Cupid, who will fill my shoes as Community Manager, and I will continue within Vortal Storm as its Chief Administrative Officer, running Vortal Storm together with Mr. Darkness.

So, it's not really goodbye if I'm not leaving, but I will take a lot more distance from the official community tasks.

I want to thank all of you for the wonderful 7 months of work I've been allowed to do within this community as its manager, but it's time to look ahead, and take on new challenges.

The Future of Vortal Storm:

The future of Vortal Storm is not etched in stone right now, but our next focus is to assemble two teams of developers. One small team to stay working on, and bugfixing, Lambda Wars.

The other, larger team will work on a new game with us, that will be applied within Steam again at a price, which is our next step forward.

We hope to see you sometime!

Husky & Darkness.

15 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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