Our first look at StarCraft II: Heart of the Swarm, the second of a trilogy of StarCraft II titles, came by way of a press event held at Blizzard Entertainment's headquarters in Irvine, CA last week.
We had a chance to attend, and Sixen of SC2Mapster has posted his comprehensive thoughts on Heart of the Swarm, as well as any information he was able to glean from the preview.
Of note, we discovered that most of your time spent in the singleplayer campaign will be playing Sarah Kerrigan, Heart of the Swarm's protagonist. Unseen in StarCraft II: Wings of Liberty is the concept of heroes, but they're making their return to Blizzard RTS games with the latest entry into the StarCraft II saga. Included will be the ability to select from a variety of specialization trees -- your Battle Focus -- with which you'll unlock new abilities through the completion of missions and leveling Kerrigan up.
A Wings of Liberty feature making its return is the ability to upgrade your units between missions. However, a new more Zerg-friendly concept is introduced in the form of Mutagen -- rather than Liberty's cash -- which you'll acquire during the campaign's missions. This Mutagen can then be spent on a variety of upgrades for your units, including allowing your Baneling to instead become a Splitterling, causing it to split into two Splitterlings.