Lambda Wars

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.## features

• 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

Source: Steam Store Description