It has been almost two years since Starcraft II: Wings of Liberty was released. Since then, fans of the Zerg have been waiting for the Heart of the Swarm expansion to tell that race's side of the story. The time has finally come for the Zerg to get their moment to shine--and shine they do. It's unfortunate that poor writing intrudes on the campaign, because the missions themselves are highly entertaining and varied, and online play provides plenty of cutthroat thrills.
Heart of the Swarm's single-player campaign serves as a great point of entry, boasting 20 missions with diverse objectives. Though they may not be as memorable as some of Wings of Liberty's finest missions (like the train robbery mission or the final stand of the Protoss), that doesn't change the fact that they are wonderful in their own right. One has you infiltrating a Protoss ship with a parasitic larva. After consuming its doomed host, the creature must slink around the ship, hiding from enemy units and collecting biomass until it evolves into a broodmother capable of spawning various Zerg creatures and destroying the vessel's engines and escape pods.
Another great level involves spreading creep (the living purple goo that oozes from Zerg structures) to wake up dormant scourge nests that can shoot down otherwise invincible Dominion ships. Elsewhere, you alternate between controlling Kerrigan's forces and commanding primal Zerg who must destroy the generators that power a psi destroyer device that makes Kerrigan's units explode. Other highlights include commanding Jim Raynor's battlecruiser, The Hyperion, during a space battle; having Kerrigan face off against a series of rivals in boss battles reminiscent of Diablo or World of WarCraft; and triumphing over a battle arena-style mission where AI-controlled infested Terrans act as cannon fodder while Kerrigan marches on a Dominion base. All this diversity keeps the campaign feeling constantly fresh.
One major difference between HOTS and WOL is the new campaign's focus on Kerrigan. Kerrigan gains levels by accomplishing mission objectives, making her hero unit even more powerful, and unlocking a tier of three abilities every 10 levels. You can switch out abilities between levels, and they range from special abilities that make Kerrigan more powerful (like shooting chain lightning with every attack or damaging multiple enemies) to powers that improve the swarm as a whole (like spawning two drones for the price of one). Generally, these are useful enough that all are tempting. However, there is one passive power that resurrects all dead Zerglings for free at your main hive at the rate of 10 or so every 30 seconds. That is pretty hard to pass up. Most Zerg units also gain three unique mutations that you can switch out between levels. For instance, you can fine-tune the acidic suicide bomber banelings to dish out more damage, increase the radius of their explosions, or make their explosions heal friendly units. The ability to switch Kerrigan's abilities and unit mutations between levels allows you to build an army that caters to your play style.
The other major change from WOL relates to research. In WOL, you often had to choose between two upgrades, but you never had the opportunity to test them in advance. In HOTS, you get to develop new strains of various Zerg units, but special evolution missions let you test both possible strains before you make your decision. Possibly the most overpowered example is the ultralisk, which is already the most formidable Zerg ground unit. You can create a strain of ultralisks that are resurrected almost immediately at the exact spot where they died. Couple that with a mutation that increases their health every time they hit a unit, tack on some hive queens following them for healing purposes, and finally add Kerrigan or a pack of antiair units, and you become practically unstoppable. This sort of thing can make HOTS' campaign much easier than WOL, but sometimes it's fun to see what unbalanced, ludicrous action plays out on screen.
Unfortunately, while the campaign is a blast, much of Heart of the Swarm's writing ranges from cliched, to mediocre, to comically bad. The single biggest disappointment is the depiction of Kerrigan. In the original games, when she was the self-described "queen bitch of the universe," Sarah Kerrigan was a great villain. She played the victim card to manipulate others into paving her way to complete dominion over the Zerg swarm. Once that was done, she mercilessly obliterated those useful idiots and mocked their grieving comrades. The old Kerrigan was manipulative, power-hungry, ruthless, and totally unapologetic about it. She had character.
The new Kerrigan is boring, and her actions are often incomprehensible. After a series of happenstances end her (entirely unconvincing) romantic subplot with Jim Raynor, she devotes all her energy toward killing the Dominion's dastardly Emperor Arcturus Mengsk. Of course, to accomplish this, she inevitably has to re-infest herself with Zerg essence and reclaim control of the swarm. This could have been the start of an interesting story about how she reconciles her recently reclaimed humanity with her role in the Zerg army. Unfortunately, Kerrigan's lack of consistency or even a coherent character arc ruins that opportunity. For example, at the end of one mission, she spares the lives of wounded Dominion soldiers, but upon returning to her ship, she orders a broodmother to wipe an entire planet without batting an eye. It feels like she just flips a coin to determine whether she's going to act like Genghis Khan or a bleeding heart.