Damsel In Distress: Is Starcraft II Sexist? (Contains Spoilers)
Kerrigan at the beginning of the game
Kerrigan, crushing pretty much everything
Starcraft II: Heart of the Swarm is the story of Kerrigan's mission to rebuild the Zerg Swarm, reclaim the power she wielded as the Queen of Blades, and avenge the death of her lover, Jim Raynor. Her goal is nothing less than the total annihilation of the Terran Dominion and the death of its emperor, Arcturus Mengsk. She sacrifices her restored humanity for greater power, only to discover later that Raynor is actually alive. She rescues him, only to face his bitter disappointment and anger over her choices. This, too, is a crime that can be laid at Mengsk's doorstep -- it's his fault that she was infested by the Zerg in Starcraft, and his actions that led to her decision to embrace the Zerg for a second time.
The emperor himself
She lands on Korhal, the capital of the Terran Dominion, tears through the city, invades Mengsk's palace, tears the door off its hinges, faces off with Mengsk, and is promptly flattened by the same alien artifact that was used to de-Zerg her in Starcraft II: Wings of Liberty. Just as Mengsk is preparing to execute her, Raynor steps through the doorway, crushes the activation device the Emperor is holding, and hurls him across the room.
Raynor, lowering his gun, as Kerrigan regains her feet
Raynor draws a bead on the Emperor with the pistol he's been saving since Starcraft: Wings of Liberty -- and then stops. It's Kerrigan, not Raynor, who seizes Mengsk, slams him up against the wall, and kills him.
The question is, is this depiction sexist? Kerrigan, after all, has just spent the entire game gathering vast amounts of psionic power. We've seen her hurl multiple people through the air, survive wounds that should've killed her, and face off with ancient, mountain-size Zerg tens of thousands of years old. She vanquished them all, but when it came to Mengsk, suddenly, she needs a helping hand. It's a valid question, particularly if you care about how women are portrayed in video games, but I don't think it's an issue here.
Starcraft's lore has a great deal of information on why the final confrontation between Mengsk, Raynor, and Kerrigan plans out the way it does. Mengsk has a longstanding reputation as a cunning, vicious, and ruthless person. He favors surprise attacks, ambushes, and treachery. Mengsk killed several billion people on the planet Tarsonis when he left Kerrigan to die in the original Starcraft. The question isn't whether he had a last-ditch weapon, only what it was and when he'd spring it.
The Xel'Naga artifact he uses against Kerrigan is also part of canon. Xel'Naga devices have nearly always been deployed to annihilate Zerg. Mengsk had apparently tuned the device to specifically attack the erstwhile Queen of Blades, which again stands up to scrutiny. Kerrigan and Mengsk worked together for years before he left her to die, her psionic patterns and genetic structure would have been matters of record, as were up-to-date intelligence profiles on her actions, both as a Terran Ghost and Zerg-infested hive queen.
Finally, there's Raynor. Raynor worked with Kerrigan multiple times in Starcraft and Brood Wars, both before and after her transformation. They're former lovers and proven bad-asses, each in their own right. The greatest single reason for rejecting the sexism argument is that the final scene of the game works just as well if you reverse the male and female roles.
Raynor didn't follow the Zerg Queen into the Imperial palace because she needed saving, he followed because he still loved her, she was his friend, and he had reasons of his own to want Arcturus dead. It's true that he intervenes in a critical moment, but he purposefully doesn't fire the killing shot. He's not "giving" Kerrigan the honor, he's recognizing that her claim to vengeance is even stronger than his own. Mengsk is directly responsible for her infestation, transformation, and the slaughter of billions.
Raynor's decision to stand with Sarah is his way of telling her that he understands why she went back to the Zerg, recognizes that the new Kerrigan is far different from the old Queen of Blades, and that he still cares about her. It's not because she needs his help. It's because that's what Kerrigan and Raynor did for each other in the old days. They were friends. They were lovers.
They were family.