THE CHARACTERS
It appears that Kerrigan will have two interesting helpers to aid her in her quest. The first one is Izsha, a female creature that represents the Kerrigan's "memory as the Queen of Blades". She will be the intelligence and battle advisor of Kerrigan, apparently having similar functions to Matt Horner in Wings of Liberty.
The other helper will be Abathur, and according to Kotaku is "a slimy, sinister blend of caterpillar and spider". Abathur will guide the evolution of the Zerg strains that Kerrigan can upgrade and will oversee the processes in the Evolution Chamber (see below).
THE MISSIONS
War for the Brood
One of the missions that has been playable at the press event bring the player back to the Terran-occupied planet of Char. But an additional problem lies before Kerrigan. There is a new Zerg Queen in town, Za'Gara, that seeks to crush Kerrigan, who now appears human and weak.
The primary mission here is to collect 100 Zerg eggs before Za'Gara does the same, so you can overrun her. Kerrigan starts with some Zergling and soon a new unit - the Baneling - is introduced. There is also the bonus objective to collect six baneling eggs, that will give you the option to purchase valuable upgrades for Kerrigan. All this must be done while Za'Gara sends numerous attacks at your main base. Occasionally, Kerrigan will run into the Zerg Queen herself and after being defeated, Za'Gara will retreat for some time, giving you space to breathe.
After the main objective is completed, a ton of Banelings are hatched and Kerrigan leads them to the obliteration of the enemy Queen.
Silence Their Cries
The second mission presented at the press-conference take place on the freezing planet of Kaldir, where Kerrigan lands to reclaim the Na'Fash brood. The most important feature of the planet is its freezing winds that immobilize any friendly and enemy unit. Except the Yetis! Thus, Kerrigan's first task is to kill enough Yetis and their, which gives you an important DNA strain that protects your forces from the freezing winds of Kaldir.
The next step is to hunt down the Protoss forces that are apparently residing on the planet and have slaughtered the Na'Fash brood. Kerrigan must destroy three com-link spires, thus disrupting any communications to the Protoss homeworld.
EVOLVING THE ZERG
The leviathan that carries Kerrigan and her advisors through the galaxy has its own Evolution Chamber. How handy! The Evo Chamber is the place where you will put the strains you collect throughout the missions and upgrade your swarm.
Similar to Wings of Liberty, players will be able to purchase different upgrades for their units, making them more powerful or versatile in combat. Furthermore, an evolution choice for the units is given, which gives them unique abilities, which are mutually exclusive as only one path of evolution can be selected. Below you can see the upgrades and evolutions that were presented at the press event.
Zergling
Metabolic Boost – Movement speed increased by 33%.
Posthumous Mitosis – A 20% chance of after dying to spawn 2 broodlings.
Rapid Genesis – Zerglings are trained instantly.
Evolution:
Swarmling – Hatches three swarmlings instead of two zerglings, the third comes at no extra cost.
Raptor - +10 HP, and leaps into battle.
Roach
Chitinous Plating - +1 armor.
Bile Ducts – +2 damage.
Organic Carapace – Health regeneration increased by 2
Evolution:
Prowler – Enables burrow movement.
Leech – Every unit killed gains the leech 10 HP (up to a maximum of 60). Also, Health regeneration increased.
Baneling
Viscous Discharge – Upon impact, slows the target by 25%.
Centrifugal Hooks – Movement speed is increased by 25%.
Rupture – Splash radius increased by 25%.
Evolution:
Splitterling – The baneling now splits into smaller explosive units when killed.
Gorgeling – After exploding, the gorgeling returns a sum of minerals and gas on the floor.
To add to this, Blizzard confirm their hints about RPG elements in the campaign. Players will be able to upgrade Kerrigan's abilities much like a role-playing character, something that was not present in Wings of Liberty and will give an unique flavor to the HotS campaign. A Kotaku screenshot reveals two of the four "specs" for Kerrigan - Spec Ops and Corruption - and TeamLiquid provides some details on them.
Spec Ops (+50 Energy)
Pulse
Energy Cost: 50
Cooldown: 10 seconds
Description: Deals light damage to all targets in a 2.5 tiles radius. Also stuns the units for 3 seconds.
Psionic Shadow
Energy Cost: 50
Cooldown: 30 seconds
Description: Kerrigan creates a Psionic Shadow of herself that deals half damage.
Infested Cortex (Unlockable)
Energy Cost: Passive
Description: Grants Kerrigan an additional maximum of 50 energy.
Corruption (+3 Armor)
Corrosive Spores
Energy Cost: 50
Cooldown: 10 seconds
Description: Target all units in a 2.5 tiles radius, all units receive an additional 3 damage. Lasts 15 seconds.
Spawn Broodlings
Energy Cost: 50
Cooldown: 10 seconds
Description: Kills the target. The target spawns 5 broodlings upon death. Massive/Heroic units are immune.
The Blizzard staff has also stated, that the campaign will span across approximately 20 missions, which puts it slightly below Wings of Liberty in terms of numbers.
Links
Kotaku.com - Source
TeamLiquid.net - Source