We are now approaching the C2 junction at Itabashi...This is ideal. I almost take a deep breath. Suppress it. This must be as unexpected as possible.
Then, in one smooth motion, I yank the door latch, shove the door open, and fling myself out of the car...
I hit the pavement arms-first...and skid, leaving not blood and torn flesh but sparks in my wake, as a torrent of stored mana floods all but a few square inches of my skin. I spring to my feet and press myself against the side wall of the highway, just in time for a car to miss hitting me by barely a centimetre...I look down: the drop is nearly twenty metres into the city below. I hope I am not overestimating the strength of this spell as I leap forward.
I have never been skydiving, or ridden a roller coaster, or done anything much more exciting than ride a fast elevator. As I go into free fall, as my entire body floods with adrenaline and my every sense tells me I am about to die, I feel something amazing, something indescribable.
Adaptation Name Change: The author has made a point of replacing any Engrish terms with better English. For example, "An Involuntary Movement", the full canon name for AIM, has been changed to "Involuntary Physical Distortion", or IPD. Other changes include Level Upper becoming Level Plus, Meltdowner becoming just Meltdown, Big Spider becoming the Tarantulas and Skill Out becoming Zero-Sum.
In canon, Anti-Skill is the entirety of Academy City's professional police force. Here, Anti-Skill is the Academy City Police Department's SWAT division.
Combining this trope with a variation of Composite Character, all of the magical Christian groups like Necessarius, the Catholic Church and Annihilatus are now part of an organization named Pax Christiana.
In-universe, Touma is now considered to be a Level 1 esper. This is not because he's more powerful, but rather because the esper ranking system has been changed to make more sense. On the other hand, he doesn't have a natural knack for picking up street fighting skills like his canon counterpart; instead of being completely self-taught, he takes self-defense lessons like everyone else. Specifically, Krav Maga.
There are now eight Level 5 espers. In addition, Meltdowner...err, Meltdown is now ranked third, Gunha is now ranked sixth, and in an inversion, Mikoto is now ranked fourth.
On that note, Mikoto doesn't have her canon hackingabilities. The in-universe explanation is that she needs to know how computers and programming work in detail, and she's not a computer person. The out-of-universe reason is probably to avoid Cast Speciation with Uiharu.
Index, who in canon was mostly The Load, is now a Guile Hero who makes use of Loophole Abuse to get around the restrictions of her Geas and uses her encyclopedic knowledge of magic to come up with highly unorthodox solutions to her problems, like the creation of a mobile church.
Maika is now a Playful Hacker...and she says that she's hacked into half the robots in Academy City. Tellingly, Uiharu thinks she might have esper powers.
On that note, Uiharu is much more confident and level headed than she is canon. To the point where she and Maika have created an extremely powerful computer that uses Uiharu's temperature control ability to operate at extraordinarily high speeds without needing a specialized cooling system.
Tsuzuri Tessō, who, in canon, was a meek Anti-Skill officer, is now Saten and Uiharu's teacher and a tough, no-nonsense ACPD/Anti-Skill officer where she chews out Mikoto for causing property damage during the Seventh Mist hostage situation.
Adaptational Sexuality: Motoharu and Pierce are straight in canon. In the fic, Motoharu is Bi the Way and is in an on-again, off-again relationship with Pierce...er, the blue haired guy whose name Touma can't remember.
Boxing Lessons for Superman: In this fic Touma has been learning Krav Maga under Yomikawa-sensei for eight years. (Granted, his only ability is Anti-Magic, but that's why he's learning self-defense).
Clap Your Hands If You Believe/Religion is Magic: Played with. Magical power is tied to organized belief in something, whether it's a mythological deity, Christianity, or possibly even America. However, magicians can cast spells without needing to believe in the deity or concept the spell is dedicated to. What's important is that enough people did believe a deity or concept and created rituals dedicated to it's power.
Coca-Pepsi, Inc.: GoogleBaidu is the Mega Corp. that cyberpunk warned us about, or so some of the more paranoid people in-setting believe.
Dirty Cop: According to Konori, some branches of Judgement are as bad as the gang members they take in.
The Great Offscreen War: The Second Korean War is mentioned a few times in the story and is the reason why so many Koreans are present in Academy City. Other than the fact that Japan and Academy City were both involved in the conflict, little is known about what happened.
Guile Hero: Touma, as in canon. Index, not as in canon.
Iconic Outfit: Averted on two counts. Index does not wear a habit. Maika has also traded in her maid uniform for casual duds as part of the remake's emphasis on smiting violations of common sense...and Values DissonantFanservice
Japan Takes Over the World: As shown by In Memoriam's interlude. To be more precise, Academy City means Japan is only the second largest economy in the world (behind China) but they're catching up.
No Koreans In Japan: Averted, if anything there are more Koreans in Japan than there are now, enough to merit trilingual streets signs in Academy City. This is legacy of The Second Korean War which is hinted at at various points in the story.
No Ontological Inertia: In contrast to canon, Touma's ability averts this. It stops powers from acting within its area of nullification, but it does nothing to prevent their secondary effects.
Playful Hacker: Uiharu, as in canon. Maika, not as in canon. This also makes her a...
Power Equals Rarity: To an extent, magic works this way - casting a spell through a ritual no-one uses anymore costs a lot less mana than a spell cast through a ritual commonly used by ordinary people. For example, it takes less mana to cast a spell in Latin simply because in the modern day it's an effectively dead language.
Switching P.O.V.: At the moment, between Touma, Mikoto, Index, and Saten. Each character also adds their own touches to the narration.
Touma, as noted above, is a First-Person Smartass, snarkily bemoaning his bad luck and the circumstances it gets him into.
Mikoto also makes snarky observations, but her narration usually portrays her thoughts as italicized Inner Monologue.
Chapter 14 of In Memoriam has Mikoto experience Harumi Kiyama's memories in a Pensieve Flashback. Kiyama's narration is fairly straightforward while Mikoto makes parenthetical observations.
Index's narration is detailed and straightforward. Even her love of food is done in the same tone.
Saten's narration is less formal and sophisticated than the other characters.
Chapter 10 of In Memoriam has narration from a third grade Saten, which is unsurprisingly childish.
Can't Get Away with Nuthin' : Literally hours after getting powers from Level Plus Saten and her friends are confronted by Kuroko and Uiharu, who tell them that Level Plus causes progressive brain damage.
Chekhov's Gunman: When Touma is talking about the weird things in Academy City at the end of the first chapter, he mentions "middle-schoolers with robot armies". The next chapter introduces Playful Hacker Maika, who has hacked into half of Academy City's robots.
In the fifth chapter Mikoto mentions being helped by a redhead in a black coat. Chapter 7 confirms it's Stiyl...er, Stephen. May count as a sort of Early-Bird Cameo.
Cordon Bleugh Chef: Index makes a meal like this in Chapter 9. Turns out she's a good cook from reading recipe books.
Cliffhanger: The third chapter ends with a bomb going off. Chapters 12 and 13 also end in this.
Curb-Stomp Battle: Chapter 5. Kuroko versus one of the bombers. Her opponent didn't stand a chance.
Death by Adaptation: Harumi Kiyama's class...although it's possible one of them survived. It should also be mentioned that Kiyama's class includes Erii Haruue in this fic.
Delayed Reaction: Mikoto's narration when she first meets Uiharu. After getting over Uiharu's headband, she describes her age, size, hair color, eye color, bare feet, clothing...and then does a mental Double Take at the bare feet. It happens again when Uiharu comments on Mikoto's pajamas.
Chapter 10 establishes that Saten and Uiharu acted more like their canonical selves when they were children. (Saten only stopped flipping Uiharu's skirt when Uiharu showed their seventh grade class Saten's baby pictures).
Discard and Draw: A subversion. In Chapter 7, Index learns that Touma has broken her geis, allowing her to use magic freely. However, the geis was apparently tied to her "quick-lookup array" which let Index search for spells in her mind quickly. The result is that Index loses this ability, but she quickly finds it's not really a problem thanks to her Eidetic Memory.
In the first chapter Mikoto mentally ticks off some of the other Level 5 espers.
When she arrives in Academy City, Index passes by Accelerator. Maika's introduction later in the chapter can also be considered this.
The third chapter references Konori Mii, though she doesn't actually appear.
In the fifth chapter, one of the hostage takers complains about hearing names, one of which is Erii Haruue. In chapter 14 it's revealed that Erii was in Harumi Kiyama's class...but see below.
Similarly in the tenth chapter one of the names is Banri Edasaki. In chapter 14 both Banri and Erii appear in the Whole Episode Flashback. Said flashback ends in the reveal that Kiyama's students aren't in comas...instead,they're all dead. (Well, one might have survived.)
Limited Wardrobe: In her narration, Index claims most of her outfits consisted of the same white dress.
Loophole Abuse: The geis that seals Index's magical knowledge unlocks whenever it senses that she's in danger as a self-defense measure. What it doesn't sense is whether Index deliberately placed herself in danger specifically to unlock the seal.
Ludicrous Precision: Touma's narration can sometimes dip into this. Apparently, his ability extends to precisely 6.39 millimeters above the skin of his right hand and forearm.
MacGyvering: To protect herself from searching spells, Index jury-rigs a portable church with a crucifix, a broken music box, a can of grape juice, a water bottle, a serving tray from McDonald's, and a piece of a Big Mac's bun. And in the fourth chapter it gets broken when Touma's arm breaks the backpack Index was carrying it in.
Magical Database: Index's mind is almost literally a magical database; she searches for spells by making a mental database query that resembles SQL. This ability is dispelled by Touma's arm but as Index has Eidetic Memory this isn't really a problem.
Mana: Index actually explains that it used to be called "life force", "vital energy" or "qi", and that the word "mana" is currently in vogue among magicians because of all the fictional works that use it.
Merchandise-Driven: In-universe, there are trading cards for many of the Level 4 and Level 5 espers. This is news to Mikoto, who wasn't aware she signed away the rights to use her likeness. When she finds out, she makes a mental note to ask her mother if she knows a good lawyer, and then wonders if there will be made-in-Chinaknockoffs next.
Mood Whiplash: Chapter 8. So Saten and her friends are all thrilled with their new powers. Well here come Kuroko and Uiharu, and Uiharu is crying...
Motive Decay: Kiyama originally planned to expose Kiraha and the corruption of Academy City to the world, but now all she wants to do is kill him to avenge the kids. Justified by the fact that Level Plus induced mental degeneration has caused her to forget what the plan was, and she most likely lacks the higher mental capacities necessary to carry it out anyway.
Mundane Object Amazement: Index is utterly amazed when she gets taken to a mall. Touma then worries that Index is going to start trying to buy everything she sees, but his fear turns out to be completely misplaced.
Not a Date: It eventually hits Touma that taking Index to a mall to make up for breaking her backpack and then treating her to lunch afterward might have other people drawing the obvious conclusion. And then Mikoto catches sight of them... Any shenanigans are preemptively cut off by explosions.
Orwellian Retcon: The author made a minor change to the end of chapter 6. The distorted voice coming out of the speaker was originally described as "A tired-sounding woman's voice".
Pensieve Flashback: Chapter 14. Mikoto sees Kiyama's memories and makes parenthetical observations.
Place of Protection: Being on holy ground generally protects against magic. Index MacGyvers a portable church to protect herself from searching spells.
Police Are Useless: Not so much useless as outmatched. Kanzaki took down an entire police station and six Anti-Skills.
Poor Communication Kills: In Chapter 5, Uiharu obliquely warns Saten not to use Level Plus. Uiharu was under a gag order, which is why she couldn't be more explicit, but even then if she had phrased her warning in a better way it might have saved Saten and her friends a lot of trouble.
She later explains to Touma that electric and telephone cables are used in magical rituals because of their modern day use in transferring energy and information.
Power Limiter: Index's geis only allows her to use magic when she's in danger. It's sensitive enough to activate just by Accelerator looking at her. Touma inadvertently breaks it.
Reality Ensues: In chapter twelve, Konori reveals that Judgement is mostly a glorified neighborhood watch with esper abilities and that Kouroko and Uiharu are actually the exception in that they take it as seriously as they do.
In chapter thirteen, Komoe wisely takes Index and Touma to the police due to the fact she can't protect them, unlike in canon.
Recoil Boost: A pyrokinetic hopped up on Level Plus uses her fire to jump to the roof a building.
Refusal of the Call: An odd variation. Mikoto likes having superpowers, and she doesn't mind helping if she comes across someone in trouble. But she's not going to do something like join Judgement or go out of her way looking for trouble, because she thinks that's a slippery slope to becoming a costumed Super Hero. (She wants to be a particle physicist instead.) Though the call is becoming harder to resist as she gets drawn more and more into the Level Plus situation while trying to help out her friends.
I have been led to believe that it is something of a Mecca for fans and writers of a certain genre of romantic media. The vast number of lilies visible in every direction does nothing to disabuse me of this notion.
Suspiciously Specific Denial: Index's attempts to hide the fact that she mentioned magic in front of Touma. Touma sees right through it...but he decides not to call Index out on it, thinking that she's probably both paranoid and delusional.
Take That: In the fourth chapter, Touma is reading a book that he thinks is boring. He gets the impression that the book read better in its original language and that its translators got lazy. The author has confirmed this refers to a Fan Translation of the A Certain Magical Index light novels.
Tracking Device: How Stephen and Kanzaki tracked Index down in chapter 13, rather than using any spell that she could hide from.
Unreliable Expositor: In chapter 9 Stephen Magnus tells Index that he secretly tried to help her escape and that Kanzaki put a completion geis on him. He goes on to say that he's willing to let the completion geis kill him if it means letting Index go free. Index accepts his words at face value, but Touma quickly sees that it's just an act to make Index go with Stephen willingly.
In chapter 13 Stephen admits that while he was trying to get Index to go with him, what he said still was true.
Weak, but Skilled: Index produces little mana naturally, but she almost literally knows every spell in the book.
Who Names Their Kid "Dude"?: Touma actually thinks Index's name is fake at first. When he finds out what it means, his response is basically this.
The World Is Not Ready: Pax Christiana feels this way about magic. More precisely, they feel the world will never be ready because magic is a dangerous force that nearly anyone can learn - and many magicians throughout history have used magic to cause death and destruction.