A mod that turns one of Valve's games into a real-time strategy set in the Half-Life 2 universe has been released on Steam after six years of development.
Lambda Wars, a mod for Valve's 2010 top-down shooter Alien Swarm, passed Valve's Greenlight process in January and has now launched as a free download on Steam. It's a standalone mod, so you do not need Half-Life 2, Alien Swarm or any other game built on Valve's Source engine to play.
In Lambda Wars you play as a commander of the Resistance or an overlord of the Combine. Each faction has its own units, abilities, buildings, research and defences. The mod focuses on multiplayer, but you can fight the AI as well as play single-player missions. Valve gave the modders permission to use its famous franchise and its materials to build the game, so all the characters, logos and terminology from Half-Life are present and correct.
The features are pretty extensive: there's a spectator mode, maps that support up to eight human or AI players, a tutorial map and an offline AI skirmish mode. There's no mention of Half-Life 3, though, sadly.
Lambda Wars is the work of a group of modders collectively known as Vortal Storm, which has been working on the project since 2008. Despite this official release, the game is still in beta. The modders want to gather feedback before launching Lambda Wars 1.0.