Sarah Kerrigan returns in full force in Starcraft 2: Heart of the Swarm, the Zerg-centered expansion for Starcraft 2. Blizzard has kept a tight-lip on the entire project for months now, with anticipation slowly building. BlizzCon 2011 is still months away, it wouldn't have been surprising for Blizzard to simply wait until then to release any information - however, the release of last week's leaked video may have pushed the schedule forward for hungry fans.

Following the leak, Blizzard have released a Campaign Trailer for the expansion, dragging attention away from the cinematic teaser and more towards the in-game action.

The trailer features a lot of baneling action, which is sure to please the inner Michael Bay in all of us - with excessive explosions. You'll also get a nice preview of the subtle upgrades to the menu system, which remains largely unchanged from what you'd see in Wings of Liberty - idle screens exist for the purpose of upgrading units, performing research and no doubt communicating with important characters from the campaign.

Let's delve into the "Heart of the Swarm" trailer to see for ourselves:

Just as the terrans could choose between unit and building upgrades throughout the campaign, the Zerg will have a plethora of mutations to aid the swarm through their quest. It's likely you'll see some old faces returning to the hive, if Wings of Liberty was any indication. For a brief moment in the trailer, it's clear the Baneling mutation choice betweeen two new units entitled either a Splitterling or a Gorgeling. While the Gorgeling wasn't described, it's likely a slower but bulkier adaptation to the standard baneling.

Here's the description of the Splitterlings we sniped from the trailer:

"Splitterlings are like flatworms in that their nervous systems are completely decentralized. Cutting one in half results in each half creating an entire new [albeit smaller] unit."

Kerrigan herself will be your protagonist throughout the campaign, providing help both off and on-mission. Heart of the Swarm will be introducing a new Battle Focus system, which allows you to strategically set what she'll focus-on prior to the mission, you'll have to plan in advance if you want to use her for sneaking, sabotage or just plain fury. Though there were three classes of Battle Focus, the only ones in the trailer were Spec Ops and Corruption.

In either event, Kerrigan was a worthy adversary from Wings of Liberty, so expect to see a versatile 'hero' fighting the good fight.

Starcraft 2: Heart of the Swarm has no official release date, but is looking ready for an early 2012 release. We'll keep you posted as Blizzard releases more information!

Source: GameTrailers