The StarCraft II modding team over at Crainy have put together a highly detailed mod that takes the RTS gameplay of StarCraft and turns it over on itself. Marines of the Dominion: Psionic Warfare is a full gameplay overhaul mod that lets you take control of a small team of Terran Marines fighting to survive an onslaught of Zerg. While next to impossible playing solo, this mod is actually really fun with friends. It comes with 5 distinct classes, each with their own unique perks and abilities. Also, you can really turn the tides of war with kill streak perks that give you access to some of the game's most bad-ass mechs!
You can find the Marines of the Dominion right now for free on the StarCraft II Arcade or through the link below.