Lambda Wars (formerly Half-Life 2: Wars) brings the struggle between the human resistance and their Combine overlords to a multiplayer real-time strategy setting. The Lambda Wars beta only requires Alien Swarm installed to play. It features 3 multiplayer game modes: Sandbox, Annihilation and Overrun, showcasing the Rebels and Combine playable factions and a full-fledged RTS interface and HUD. There is also a singleplayer tutorial and a handful of singleplayer missions.

StrangerDanger says

9/10 - Agree Disagree

Played Beta 2.3.6 The game has come a long way. The units control very well. The abilities are really cool and are authentic to Half Life. The units are fun to use, the resource system is not too bad either.