Starcraft II Heart of the Swarm Trailer Intros Fresh New Units (VIDEO)

The Zerg-focused expansion to Starcraft II, subtitled Heart of the Swarm, will breathe nourishing new life into the powerhouse strategy title with all new units soon at your fingertips. For those who don't know how this whole real-time strategy game expansion pack thing works, imagine you bought a fancy new chess set and six months later you get all new pieces with different moves. It's like that but with way better pieces than that silly little horse and castle.

Our old friends at IGN provide us with this Blizzard-produced look at the new units of Starcraft II Heart of the Swarm. Get ready to rewind.