These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Mengsk does mention he feels like Kerrigan is his biggest mistake, but the game leaves it ambiguous if he actually feels guilt for creating one of the biggest mass-murderers in Koprulu by doing so or if he is just pissed off he created the biggest obstacle to his plans. Either way, there are no more doubt about him being a bastard. For the matter, is Mengsk a hypocrite who is just trying to save his own skin, or does he genuinely believe he is the last chance of survival humanity has?
The game doesn't specifically says why Kerrigan abandons Niadra, so this part of her attitude is completely up to interpretation. Did she do that because she was disgusted about what she just used her for? Or was this just a You Have Outlived Your Usefulness caused by what remained of the Dark Voice's influence? Could it be because the ship teleported to Shakuras and thus might be out of range for communication? Could it be that Amon is blocking Niadra's connection to the Swarm?
Many fans complained that Raynor's vow to kill Kerrigan or Fenix's death weren't mentioned in Wings of Liberty. Both are referenced when Raynor finds out that Kerrigan has turned back into the Queen of Blades. The scene implies that Raynor mentally divorces the Queen of Blades persona and Sarah Kerrigan, and that he was saying he would kill the Queen of Blades when he had the chance in Brood War. StarCraft II was about doing that without killing Kerrigan; when he sees that she's voluntarily turned back into the Queen of Blades, the rationalization seemingly blows up in his face. Hence his initial reaction.
As noted on the YMMV page for Wings of Liberty, it was pretty dickish for Raynor to kill the Tal'darim, defile their temples and steal their artifacts to sell for money. What's that? It turns out the Tal'darim work for Narud and worship Amon? Oh, okay then, fry them.
As well, some fans complained about the Retcon that the Tal'darim were just a splinter group on Aiur serving Ulrezaj and had no influence beyond Aiurs since they were stranded there, and Blizzard's explanation that the Tal'darim were a larger group that the Aiur branch was just a small part of seemed like a Hand Wave. With the reveal that they worship Amon, who is very likely the mysterious entity Ulrezaj serves, suddenly their role in the game makes much more sense.
Broken Base: Many fans were generally unimpressed with the story in Wings of Liberty, not really hating it but not finding it all that great. This game's story, containing several Retcons to deeply engrained lore, coupled with many of the same storytelling problems that first game had (Cliché Storm, etc), pissed off a lot of the more dedicated fans.
If there was any doubt about Mengsk being one before, he definitely classifies as one now. Kerrigan is now de-infested, she and Raynor are cooperating peacefully with Valerian as they experiment on her, and he has control of Char. Perhaps he could bury the hatchet, leave his enemies alone and all could be well. Well no, he attacks the facility to try and kill Raynor and Kerrigan, is implied to be willing to kill Valerian to do it, and during the course of the campaign resorts to nuking his own bases of power, killing off his own citizens, to protect himself from the Zerg.
Mengsk: I made you into a monster, Kerrigan! Kerrigan: You made us all into monsters.
Another moment is when he callously abandons his own soldiers to die to try and kill Kerrigan and Raynor. More specifically he talks about how "all those brave men will have to die". The soldiers are confused by this....than the blasts start erupting. As the soldiers scream, Mengsk venomously tells her that Kerrigan and Raynor can "burn together."
Narud, for, amongst other things, resurrecting an Evil GodOmnicidal Maniac and doing experiments on Stukov, reinfesting him in the process.
Because Kerrigan was the first game's Big Bad, and even today dances the line between Anti-Hero and Villain Protagonist, she can come across as falling into this trope. Is Mengsk an evil bastard? Certainly. Does he deserve to die for his crimes? Most would say yes. Does this justify all the Dominion soldiers Kerrigan massacres to do it, especially after an early cutscene reminds her that many of them are normal men and women with loved ones? That's trickier.
Kerrigan herself acknowledges, in a conversation with a captured Protoss who tries to guilt-trip her over her actions, that "I may have more blood on my hands than you". Of course, she finishes with, "but we're all still killers in the end", which is not untrue either. Especially considering that the list of people who don't try to kill her on sight is pretty short (Jim Raynor, Valerian Mengsk, Abathur, Izsha, The Ancient One temporarily, Stukov).
In a setting where there's war, everyone can become a Designated Hero. Even our dear Raynor has admitted "sending good men to their deaths" in his fight against Arcturus. And really, if Mengsk just surrendered himself instead of sending so many men and women with loved ones to stop an all powerful Physical God just to save his own skin, Kerrigan would've had no reason to kill them.
Given what the story actually entails and reveals about her Queen of Blades persona, this trope is actually somewhat subverted. Queen!Kerrigan was essentially an emotionless, brainwashed slave of Amon's reprogramming of the zerg to make them even more hostile and vicious, and wasn't entirely responsible for her own actions. The entire game is about her trying to to preserve her new!old conscience against the desires of the zerg-who are fully revealed to be a simple Draco in Leather Pants situation, being The Social Darwinist as a species even out of Amon's control-and she finds it, becoming a full, sympathetic Noble Demon who is just as much a Restraining Bolt on the Horde of Alien Locusts as a ruler...though she's still a Villain Protagonist, just A Lighter Shade of Grey than before.
The million dollar question remains tough: Was this the way it was originally planned or did Blizzard decide along the way thy didn't want Raynor to kill Kerrigan after all because they just liked her too much? There are subtle hints in Broodwar that point to both. Kerrigan being exausted and down after her MoralEventHorizon is a clear hint to a lack of free will.
Kerrigan herself makes the campaign a breeze. She starts with two spells, one of which is basically Yamato Cannon with no charge time and lower energy cost, the other an AoE stun with damage, and she has an innately high energy regeneration rate. From there she moves on to doubling the health and attack rate of allies for a time, spawning overlords instantly, summoning an army of primal zerg instantly with drop pods, and healing allies nearby. If you know how to use her abilities properly and micro her carefully, Kerrigan can solo a lot of missions. As an added bonus, while Kerrigan is far from indestructible (in fact on the last few missions she die very easily if the player is careless if she's at a high level), she respawns for free at your main hatchery/lair/hive sixty seconds later.
One of her abilities creates Broodlings whenever she kills a unit, either with her attack or with an ability. One of her ultimate abilities Apocalypse lets her deal 300 damage to all enemy units in a large area of effect. Nuke a base's defenses and all of them create Broodlings to attack what's left. Granted Apocalypse has a huge cooldown of several minutes, but one use is usually going to be enough.
She can also spawn a bunch of banelings right on top of her targets. Which bypasses the banelings only weakness and results in the instant liquification of said targets.
And speaking of banelings, a particularly hilarious game breaker is to take the triple zerglings and jumping banelings, create a crapton of zerglings and morph part of them into banelings. Even hybrids are powerless against the seemingly infinite tide of big green grenades jumping over the Insurmountable Waist High Fence of zerglings. To summarize - there is almost no situation in the entire game (anything except combat against air units) that cannot be solved with enough Banelings, especially with how cheap they are.
Also, as in Wings of Liberty, the campaign involves a lot of tech and upgrades that aren't present in multiplayer. It's a bit more obvious here what those upgrades are because we already have a baseline for what the Zerg are "supposed" to be like. Most of the exclusive mutations (IE triplings vs jumplings) are absurd, but even some of the defaults are wacky: Hatcheries that produce tons of Larvae without Queen injects? "Swarm Queens" that have a better heal spell and are fast enough off creep to serve as legitimate combat units, like a Hydralisk fused to a Medic? Overlords that spawn with their speed boost automatically researched? The objective with each campaign seems to be to make the starring race seem unbeatably strong, and Blizzard have definitely succeeded. On the other hand, speed aside, overlords have lost all their other abilities, including the ability to carry units, detect cloaked units (gone since SC 1) or morph into overseers (who had a number of abilities including the aforementioned detection).
In Wings of Liberty, Raynor said to Orlan he ought to kill him when he'd captured him after trying to sell him out to the Dominion, but he might need to hire him someday, and hands him over to Mira as a prisoner. This time around, Orlan is hired to hack the Dominion network to find out where Raynor is imprisoned, after the Raiders fight Mira to free him.
Also in Wings, UNN's Donny Vermillion once accused Raynor of allying with the zerg to overthrow the Emperor, which is exactly what he did in the final mission.
A more minor example with the Hellion. One of the unit's Stop Poking Me quotes has him say "Like a bat out of..." before stopping. In heart of the swarm it gets anew form called the Hellbat.
Seeing Zurvan. When you are trying to wake him up by feeding him, with what you see of him, the player would guess he's some Sarlac thing. When he wakes up, turns out all you were seeing was his mouth—he's huge.
The entire final mission. You're not facing the standard terran fare, you're facing the mercenary upgrades of them. Things get really heated when the Prides of Augustgrad shows up, which are a pair of Jackson's Revenge (or improved versions of the Loki) Battlecruisers. And these things respawn. And if that wasn't enough for you, make it to Mengsk's base or wait 22 minutes and the Odin of all things reappear. You know, that war machine you had in the last campaign that mopped the floor with the entire dominion defense force?
Inferred Holocaust: Kerrigan routinely is contacted by broodmothers wishing to rejoin the Swarm, and Kerrigan tells them the price of admission is to infest a world. The evolution missions also take place on planets you don't visit in normal missions, but are in the process of being invaded by another broodmother. All of the planets targeted are military strongpoints, but it's unclear whether they also have civilian populations.
Magnificent Bastard: Duran/Narud manipulated the Dominion, UED, the Protoss, the Zerg, and the leaders of the four factions, all towards a plan to create the Hybrid and revive Amon while marginalizing potential threats like Kerrigan.
It seems that developing/regaining a conscience after being freed of the Dark Voice's influence has not made Kerrigan any less clever. She just feels bad about tricking a Protoss mothership into taking a broodmother larva on board, inside of the person they were trying to rescue. Ladies and gentleman, the Queen of Blades is back, baby.
Valerian, assuming he takes the throne at the end of Heart. He ascends the throne with most loyalists of his father's out of the way (the numbers having already dropped due to Raynor's expose in Wings), good publicity with his people (by helping in the evacuation) AND with Raynor's Raiders personal friends of his, and possibly Kerrigan too. His position is more secure than his father's ever was.
Memetic Molester: Abathur wants a sample of Kerrigan's essence. Not helped by the fact it's revealed he was the one who put her in the chrysalis that first turned her into the Queen of Blades.
Just in case there was still doubt about Mengsk being a bigger asshole than Kerrigan is in her current state, he proved it to us again by attempting to self-destruct the ship where Jim is retained in hope to kill both him and Kerrigan in the blast, uncaring about all the Dominion forces still inside it. Their reaction of panic and horror remove any possible sympathy you could still have for him. Even Valerian, his own son, thinks Mengsk need to be overthrown after seeing this.
Mengsk goes even further during the invasion of Korhal, where he calls down nukes inside a densely populated city. By this point, he's showing less regard for the safety of the people on his own planet than Kerrigan is. And she's invading it!
There's also the part when he has his forces keep firing on the Hyperion even though Valerian, his own son is onboard it. The saddest part is that Valerian is the least surprised person onboard.
The Zerg, particularly Abathur and the Primal Zerg, are obsessed with "essence" to the point of Cargo Ship. It's of course a play on their "purity of essence", and it's made clear that the term is used for genetic sequences that could strengthen them if assimilated. Still, "we must absorb their essence" and the many permutations of the phrase sound silly, and after you hear the word repeated over and over and over until the end of the campaign, it will likely just sound sillier each time. It gets worse with Dehaka, who apparently based every one of his responses around the words "essence" and "collect". The writers were apparently aware of this, since some parts (including the argument between Dehaka and Zagara) play it for laughs.
The leader of Narud's protoss is so OUTRAGED at everything you do it's hard to take him seriously.
See the building that enables Swarm Host? One of the unit-enabled icon in it looks like Scaredy-shroom. It doesn't help that Swarm Hosts are basically shroom-on-four-legs.
Zeratul putting his hand over Kerrigan's face and saying "BELIIIIIIEVE" as he gives her a vision of Zerus.
Kerrigan slamming Narud into the wall while riding a Nydus worm.
Offscreen Moment of Awesome: Jim Raynor's fight with Nova. We only see the set-up, and all we know about the aftermath is that they both survived, but its safe to assume the entire facility was destroyed.
One-Scene Wonder: The game makes a big thing about spawning a new broodmother named Niadra and giving her the objective to destroy the Protoss, but she is abandoned on-board a derelict Protoss vessel with her brood after just one mission. Given her last few lines, we will be seeing her again in the Protoss campaign.
Nova, seen only in the second mission before disappearing for the rest of the campaign.
Romantic Plot Tumor: Many fans believe the romantic plot between Jim Raynor and Kerrigan is this because they feel the romance is forced and takes away meaning from the plot of the first game, despite justifications from the story author. The other half of the audience are begging Blizzard on their forums to give Jim and Kerrigan a happy ending in Legacy of The Void. But since that expansion is supposed to be centered on the Protoss (and because of the dislike of their romance mentioned earlier) this leaves the first half of the audience to fear their romance is taking over the plot.
Scrappy Mechanic: Blizzard's recent introduction MMR decay, which makes players start from lower divisions based on how active they are. For example, if you are in Masters but don't play any games for a month or two, you can find yourself bumped down to Silver. This has led to situations were extremely skilled Masters level players are getting bumped down to the lesser skilled divisions, resulting in a lot of Curbstomp Battles.
The campaign starts off with several tutorial-like levels. In addition, the protagonist will lean on the fourth wall a bit to nudge the player (though without What the Hell, Player?, more like "For your information player"—such as "Hey, I should use X ability right now"). Finally, the interface now contains more direct hints ("Move hero here," "Click the Mutate Structure button"). This "assistance" persists into at least the second-highest ("Select only if you are a StarCraft veteran") difficulty level.
Izsha will inform you it takes three Drones to mine Vespene at maximum efficiency right up to the final mission, and if you put off going for an optional objective, she pops in to remind you about them.
On that same note, Izsha's recommendation to make Zerg Units that can attack flying units will pop up on a frequent basis towards the end of the game, too.
The game simply feels more "hand-holdy" than previous installments. New abilities given to characters will be the only solution to the current situation when the ability is introduced, which, while obvious enough in and of itself, is accompanied by someone pointing out exactly this: "Use this button to solve the problem!"
Buildings now offer more information when selected—"This building allows creation of X, Y and Z units" features prominently on the command card. (Although this may simply be the analogue of Terran or Protoss production buildings where you actually have to *click* those buttons on the command card.)
Two different versions of the GUI used to give orders to units now exist. One is the "standard" array of buttons (at least six commands for any combat unit) while the "Simple" version offers "Move," "Attack" and special ability sections, excluding items such as Patrol or Hold Position.
Strawman Has a Point: Kerrigan already dances on the edges of being a Villain Protagonist, then comes this exchange. Arcturus's words do not change the fact he had a major hand in Kerrigan's rebirth as the Queen of Blades and the creation of the Hybrids, but his rebuttals to her are a bit more convincing than hers to his:
There's something endearing about young Broodmother Niadra and the way she tries her best to grow up... even if her 'doing best' means being a Xenomorph-expy.
The first time Broodmother Zagara meets Kerrigan in the leviathan, she is basically doing a certain Victorian gesture of respect, in which one lifts one's own gown a tiny bit while bowing. She continues being Kerrigan's posse through the game.
The broken-tusked Zerg that's always near Kerrigan in cutscenes near the start of the game, her interactions with it come across as being a bit like a dog and its master.
That One Achievement: Of the Mastery Achievements, there's a particularly large player agreement that "Premature Evacuation" for the Rendezvous mission is the most annoying of the lot; having to destroy ALL the Dominion structures before the Zerg reinforcements arrive after a 15 minute time-frame...with nothing but Zerglings, Queens and, at this point in the game, a fairly weak Kerrigan hero-unit.
That One Level: On Brutal, The Crucible is this which is basically a Zerg version of of Wings of Liberty's turtling mission, All-In, to protect a giant chrysalis. Hardly a surprise either since it's the one Heart of the Swarm mission where you don't have an overpowered hero unit at your disposal. (Unless you don't count Niadra)
Years ago, a cinematic was leaked depicting the hypothetical end of Heart of the Swarm. And when the game was finally released... that scene was recycled and used again, albeit with a few tweaks. Those tweaks really change the meaning of the ending though, despite some scenes having been reused.
It didn't take long after the first game to figure out that Emil Narud was Samir Duran. Some fans speculated though that they may have been rivals working against each other, or they were actually different characters. Turns out no, they were right all along.
Villain Decay: Mengsk, despite being Big Bad of the game, is largely demoted to a secondary character, and his motivations are no longer explored in any detail.
The Woobie: Raynor keeps being this. At least half of his effort from Wings of Liberty are seemingly completely destroyed by the beginning of this game.
Iron Woobie: Stukov; after getting killed by Duran and having his whole faction killed by the original Queen of Blade in Brood War (making him a Senseless Sacrifice), then being resurrected as an infested terran and cured, it turns out he has been infested again, as well as kept prisonner and experimented on by Narud for entire years. He can never goes back on Earth, and even if he could, there would be no place for him, since he is half-Terran half-Zerg. Yet, you don't see him mourning about it. He even seemed a little excited about possibly fighting "a good death" against Amon, since he has no other purpose left in life.
Jerkass Woobie: Kerrigan, big time. She has barely recovered from being Brainwashed and Crazy into acting like an Omnicidal Maniac for entire years, and shit just start being thrown at her again: Mensgk keeps wanting her dead, her boyfriend is apparently killed, and when it turns out he is alive, he is so horrified by what she has done to herself that he doesn't want anything to do with her anymore until the finale. Any wonder she is so pissed off?