Anticlimax Boss: Jeffiroth, who turns out to be completely pathetic when his hair gets frozen. The Grand Master Fangirl could qualify as well: she gets defeated by FF.net's terms of service.
Arson, Murder, and Jaywalking: The heroes have landed on the City of OC, subverted the Mary Sue's intimidation power, easily destroyed Marly-dono's prospective army, and are about to storm his lair. "Agh! And they're throwing their unconscious bodies into my beautiful rosebushes! THOSE WERE RAISED BY HAND, YOU BASTARDS!"
"Organization XIII was not a nice group of sort-of-kind-of-former people. They toyed with minds, they twisted relationships, they used lives as tools, they manipulated innocents, they spread chaos, they captured hearts, they lengthened the lines at the DMV and they commanded Heartless."
Ballroom Blitz: Aku-chan interrupts Destiny Sanctuary Peak High School Academy Grammar School's Spring Fling Formal Prom Hop to create Gutless out of the student characters. The protagonists interrupt his plan right back.
Berserk Button: As Vexen clearly enunciates, “Nobodies. Do not. Have. Hearts.”
Bowdlerise: Parodied with the Gutless' name. Vexen "was going to call them the Nutless, but Disney put their foot down. Some nonsense about not scaring the children and lawsuits, something about a VHScover or something."
Cerebus Syndrome: The first ten chapters poked fun at all of the clichés and themes in the Kingdom Hearts fandom while having what is little more than an Excuse Plot; the next two ramp up the seriousness of the plot (if there was any to start with) while keeping numerous pieces of snark.
Crack Fic: Vacillation Heights changes between this during the day and Dark Fic at night.
Creator Cameo: All of Organization VI appear in some fashion, but Gexegee (the actual writer) deserves special mention. She wrote herself in as calling for Xaldin from the bedroom, asking him to bring more whipped cream, and then being thrown out into space.
Designated Villain: invoked In Inept Crossings, Lexaeus meets InuYasha, who is baffled as to why Lexaeus doesn't want to antagonize him, and in fact, orders him to do under the fear of Inept Crossing's ruling Semes.
Dramatic Wind: Lampshaded in the text, describing it as improbably slow-falling and dramatic.
Duck!: Inverted, as The Llama Song reference ends one verse with the animal, though when applied to the giant, shapeshifting llama-thing the protagonists encounter, Vexen exclaims "duck" to warn of the giant blade that is just about to swing over their heads.
E = MC Hammer: Vexen scribbles on a chalkboard in this manner to explain his two theories of how Xaldin and Roxas remained safe after the Reset Button.
Plot Hole: The story seems to span the length of a day (or at least, some short period of time), yet one of the Semes says that he and the Grand Master Fangirl had been conspiring for months to spread the Gutless to the canon world.
Power Gives You Wings: The remaining energies of the Yaoi Cannon, when the Big Bad unlocks them for Mansex, gives him wings among... other garish outfit changes.
“Nevertheless,” Lexaeus still had his fierce gaze locked on the imposter Nobody as he pulled his tomahawk up out of the ground. “Larxene is our comrade-in-arms and we will not stand for what you have done to her. In the name of the real Organization XIII—prepare to die.”
Relax-o-Vision: Double-subverted. Right when the protagonists are about to test their theories on Xiggy-kun, the narrator announces to switch to a description of kittens, but since she has no kittens, she switches the plot to the second line in-waiting.
[Sakura-Rose:]“You’ll never defeat me, you hideous beast, because I represent all that is pure and good and light in the world, and YOU are an evil creature with no heart and I have a heart and it holds nothing but love for ALL LIVING THINGS! And you’ll never be able to scare me, either! My will is as strong as stone!”
“Really?” Lexaeus asked lamely, and with the slightest movement of his hand, Sakura-Rose was crushed to death beneath two tons of irony and a gigantic summoned slab of rock.
Also twice with Jeffiroth: the first time with a 'get on with it' and the second by snapping his Badass Locks off.
Throw the Dog a Bone: After suffering through the cake running gag for the majority of the fic, Vexen gets to kick back and relax in a comfortable lounge in Chapter 10 instead of having to fight hordes of Bishonen Gutless like Xaldin and Lexaeus.
"Let's go through the checklist," Xaldin suggested, one eyebrow raised high over the other as he examined their surroundings quizzically. "Dark skies?" "Check," Lexaeus nodded. "Foreboding, overly complicated architecture and/or some kind of ruins?" "Indeed," Vexen confirmed. "Epic-sounding technopop and/or metal music in the background?" "Yep." "Cryptic clues and references to the end of things, and/or excessively pretentious area names?" "We have stepped into the Haven of Wasted Epiphanies," Vexen announced, reading from a convenient nearby sign. "Up ahead is the Village of Twisted Thoughts and the Subdivision of Broken Endings. Triple check." "Yes. I thought so," Xaldin sighed. "This is a Final World if ever I saw one."
Videogame Settings: As the exposition describes, the barricade Lexaeus and Vexen form in front of the darkest tower makes the building resemble an Ice Palace.