Half-Life 2: Wars brings the struggle between the human resistance and their Combine overlords to a real-time strategy setting. The Half-Life 2: Wars Beta, which you can download here on Desura, requires you own Half-Life 2: Episode 2 to play (does not need to be installed)! It features 3 multiplayer game modes: Sandbox, Annihilation and Overrun, showcasing the Rebels and Combine playable factions. Additionally it features a singleplayer mission mode.
Gameplay video of the overrun gamemode. Can be played with multiple players. Defend against waves of antlions until your main buildings are destroyed.