The second installment a StarCraft II, called Heart a the Swarm, will feature an entirely new single-player campaign focusing on the Zerg faction. Blizzard talked about how that will work previously, but t' date hasn't revealed much about how the multiplayer part a the game will be changing. We can expect concrete details at BlizzCon 2011 later this October, but in the meantime, Blizzard be sending out teaser images for some a the new units...