Lambda - Co-Op Framework (Beta)

Have you ever wanted to play the Half-Life 2 series with your friends online? Then Lambda is exactly what you are looking for.
Lambda aims to provide seamless multiplayer support for the Half-Life 2 campaign maps, as well as user-created campaigns.

Test Server - NOTE: Might be undergoing for tests sometimes, but feel free to join.


  • Level scenes reworked to be multiplayer friendly
  • Full player and object transitioning between levels
  • Enemy scaling based on skill level and player count
  • Visual improvements
  • Legacy Half-Life 2 aspects such as view bob, view lag, sprinting, AUX power counter, and more
  • Dynamic crosshair – adapts to colors given by the pixels aiming at
  • Underwater bullets
  • Passenger seats
  • Mapscripts for each campaign map for modifying logic and extra gameplay enhancements
  • Ability to create your own story
  • Some hidden easter eggs
  • Shout outs based on player surroundings.

Supported Games

Half-Life 2

  • Full support.

Half-Life 2: Episode 1

  • Planned

Half-Life 2: Episode 2

  • Planned

Campaign/Story Creation
This is currently a work-in-progress, but will be documented soon. Here are the current specifications:

  1. Whatever Half-Life 2 uses already works
  2. For transition support, your map must have an info_landmark, trigger_transition, and trigger_changelevel. Check out the Valve Developer Wiki for more information
  3. Information about round setup and other basic rules

Bugs and the Code
You can find our GitHub repository at, please report all your issues there.

Click here

half life source when

To be honest, I never even tried that in Garrys Mod but it might be possible, so who knows :v

Edit: I did take a look into it, its not too bad but requires ofc for each map as always specific treatment, but I will actually give it a try once ep1 and ep2 are done.

If I had a dollar for each crash that occurred when developing, I could afford a ferrari by now :v:

Jokes aside, glad to be a part of this. Finally the beta is out. Good job Matt

Let everyone have a KitKat, revamp HL3.


It isnt out yet…

For all of .5 seconds I was hyped for some kind of functional programming framework.

Nice work regardless.

I thought it was a framework for building gamemodes that involve running to a goal, jumping over objects, etc.

A bit like JS_CO-OP from HL2:Deathmatch but scriptable.

There used to be a JS CO-OP map where you are in a dock area with multiple cranes and platforms and someone has to drive the crane and pick up the other players in a container and move them between the platforms to get to the other side. Then someone else hops in the next crane, etc.

I’m not familiar with the map in that video, but I was a big fan of the js_build_puzzle maps. There were about 20 different maps, each of which would have about ten puzzles on them. Some of them were incredibly hard, but pretty fun to run with a group of people. Might try rounding those maps up tomorrow…

A lot of the later ones had at least one crane puzzle similar to what you describe.

Sorry for any further derailing.

Are those the ones where you pick up props with the gravity gun, and when you punt it, the prop freezes in the air? I grew up on those servers, as well as another kind of Coop. What you did was go through portals to different areas of the map with different challenges, it could be anything from surfing to gravity gun basketball. If you beat the level, you would get a battery that you would put in a slot. Still don’t remember what happened when you got them all in, though…

When I repurchased HL2:DM on an alt account, I was disappointed to see that all these servers were dead.

[editline]15th October 2016[/editline]

Also, OP, what makes this better than Synergy? That’s free, but you have to pay for Garry’s Mod.

To be fair, the framework isnt quite complete yet, still targeting to get all the campaign maps to work however I do have plans for a DM gametype.

Regarding Synergy, you could just play and see it for your self, not going to bash or praise it.

I had a server that ran the HL2:DM puzzle maps back before GM13 and it was fairly popular. It’s pretty difficult to get a lot of the player-movement based parts compatible but It’s possible this already has that handled.

As far as I know Synergy doesn’t have P2P support, so this would probably be easier to play with friends.

Also, since it’s in Garry’s Mod, there’s plenty of addons you can use with this.

Oh boy, here we are, with a new update! You can play the HL2 campaign from start to finish now, alongside with other new features.

We are also looking for help with Episode 1 and 2 (or even HLS). To get started, you can find the code on GitHub.

The server is also working again, connect at steam://connect/

i dunno why, but when i tried to host this on a dedi a bunch of different functions simply didn’t work, like player.GetCount() or game.GetGlobalState()

Are you on some older version perhaps?

oddly enough after running validate in steamcmd the issue’s been resolved, im not really sure what was wrong

Appears your server was out of date, player.GetCount was introduced by the april update:

I am kinda sad that the floor is lava is more popular than this… :disappoint:

apart from that first issue, this is really awesome and honestly seems like something i’d love to help out with, i might have a crack at doing episodic stuff when i’m free c: