Adaptation Explanation Extrication / Live-Action Films

• Annihilation (2018): The expedition team is made up entirely of women for no apparent reason. In the book it’s revealed that the Southern Reach deliberately arranged the team that way to introduce yet another variable into their experiments with the Shimmer, which is also why most of the members are scientists and why the previous expeditions had similarly odd rosters: they’re not expected to stop the Shimmer; they’re sent there to help the Reach learn its capabilities and behavior. The movie excises this (along with almost everything else that happens with the Reach during the trip), with the result that the military seems to send a group of untrained scientists charging into a lethal Eldritch Location just because.
• In Battle Royale Shuya and Noriko are shot and killed (off screen) by Shogo, but turn up alive later during Shogo's confrontation with Kitano, with only a throwaway line about Shogo hacking the computer system as explanation. Particularly egregious since no mention is made of Shogo being able to do so, and Shinji successfully hacked the system earlier in the film. Fans of the book will know, however, that Shogo hacked the system before the program began to figure out how to disarm the explosive collars worn by all participants, and transferred into the class selected to participate in order to save as many people as possible.
• The Big Sleep had to omit any references to pornography or homosexuality thanks to The Hays Code. As such, it's left unexplained what's going on in the back of Geiger's store that's so secret, what sort of blackmail material he had on Carmen, and why that one guy hid Geiger's body and shot the man who killed him. In the book, the explanations are, in order: it's a black market pornography business; he had nude photographs of Carmen; the guy was Geiger's lover.
• Blade Runner is loosely based on the novel Do Androids Dream of Electric Sheep?, where it's a major plot point that most of the world's animals have gone extinct; the novel explains that owning live animals is a popular social trend due to animals' rarity, and people regularly buy robotic facsimiles of animals if they can't afford real ones. The movie doesn't really explain this, but keeps a couple of references to it. For example: Tyrell owns a robotic owl, and Zhora uses a robotic snake in her dance act (commenting "If I could afford a real snake, do you think I'd be working here?" when Deckard asks if it's real). One of the questions in Rachael's Voight-Kampff test also hinges on the idea that collecting dead butterflies would be a sick thing for a child to do, while another hinges on the fact that owning calfskin items is illegal.
• The Chronicles of Narnia:
  • In The Lion, the Witch, and the Wardrobe, after the kids become kings and queens of Narnia, the narration tells how they ruled successfully for years and years and were given nicknames: King Peter the Magnificent, Queen Susan the Gentle, King Edmund the Just, Queen Lucy the Valiant. In the film, they're crowned with these names while still kids just after winning their victory, which makes them seem slightly ridiculous and over-the-top — especially in the case of Edmund, whose main contribution to the plot was betraying his siblings to the White Witch before he got better.
  • It's explained in the book that the White Witch's Turkish Delight is enchanted to be so addictive that a person under its spell will keep eating it until it kills them, making Edmund's betrayal over a supply of candy seem far less petty.
• In the original Congo novel, Karen is a Corrupt Corporate Executive whose only interest is finding diamonds for her firm. She loads an abandoned mine with dynamite near a dormant volcano in an effort to locate more diamonds and the resulting explosion triggers an eruption that destroys the abandoned city and forces them to Outrun the Fireball. In the Congo film, her character is a lot more sympathetic, the reason she joins the expedition is to find her Canon Foreigner boyfriend who was in an earlier expedition that vanished and the dynamite thing doesn't happen. The great eruption in the film is reduced to a random coincidence. The book also has explanations for the killer gorillas (guard animals gone feral, but smart enough to pass their training to their descendants) and why the city was abandoned (the traits the company wants the diamonds for made them worthless to the original inhabitants, who had no reason to stay when the more desirable ones were gone).
• Denis Villeneuve's Dune (2021) is somewhat vague about the finer points of Baron Harkonnen's plan to destroy House Atreides, which might leave some viewers wondering why he goes to such great lengths to kidnap Dr. Yueh's wife to force him to betray the Atreides (when he could presumably have just bribed him), and why the Atreides (who otherwise pride themselves on their extremely tight security) apparently never consider the possibility that Yueh might be a traitor. The book explains that Yueh is a graduate of the Suk School, an elite medical academy where graduates are subjected to mental conditioning that makes them physically incapable of taking a human life—making him the one member of the Duke's household whom no one would ever suspect of being a traitor.^note  Graduates of the Suk School are the only doctors entrusted to treat the rulers of Great Houses, who live under constant threat of assassination. House Harkonnen discovered that it was possible to break the Suk School's conditioning by forcing a person to take a life in order to save another life (putting them in a situation where either course of action would result in someone's death), which is why they could only get Yueh on their side by threatening to kill his wife.
• In Edge of Tomorrow, soldiers use variety of guns but Rita Vrataski uses a Cool Sword instead. Why she and only she is using a melee weapon is never explained. All You Need Is Kill from which the movie was adapted explains why. Guns have limited ammo which means no matter how good Rita will get she can only kill so many aliens in a single battle, and a melee weapon removes this limitation. On the other hand it's Difficult, but Awesome to use and the only reason why Rita is capable of using it effectively is because she was stuck in "Groundhog Day" Loop and had as much time to train as she wanted.
• Ender's Game:
  • In the film, the xenocide of the Formic species is presented just as negatively as it was in the book, but it's never actually explained that the Formic War originally started because of an interspecies misunderstanding, as the Hive Mind Formics were incapable of understanding humans' individual consciousness, and didn't realize that they were killing sentient beings until it was too late. In the film, everyone (Ender included) seems to agree that they're a legitimate menace, only questioning the methods used to defeat them.
  • Ender's decision to leave Earth to search for a new Formic home world also receives far less explanation than it did in the book, largely because of Peter and Valentine's side plot being cut. In the book, it was explained that the political situation on Earth made it impossible for Ender to return to Earth, as the Second Warsaw Pact wanted him dead, and America and its allies wanted him on their side in the coming war with Russia. Also, it was explained that the death of the Formics had led to an extraterrestrial colonization program, and that Ender had accepted an offer to govern a colony; in the movie, he just aimlessly goes off to wander the cosmos alone, with no obvious destination in mind.
  • There's also no explanation for humanity's sudden technological advancements. In just a few decades, humans go from jet fighters being the epitome of aerial warfare (Mazer Rackham flies an F-35 in a flashback) to starships capable of beating the Formics back to their homeworld. We are left to assume Imported Alien Phlebotinum thanks to all those Formic ships that fell from the sky. It's mostly the same in the books too, except the books feature two Formic invasions. However, even the First Invasion took place when humans already had hundreds of ships prowling the Solar System and gravity-manipulation technology (according to the prequels). The prequels also show the clear attempts to preserve the Formic ship for study and the foreknowledge of the impending arrival of the main Formic fleet (i.e. the Second Invasion).
  • If you didn't read the book, you could be forgiven for not realizing that the Mind Game is a Wide-Open Sandbox rather than a simple linear fantasy game — which is problematic, since the famous "Giant's Drink" sequence can end up looking a tad ridiculous if you don't know that. With the Mind Game as a sprawling, open-ended universe, it's understandable that Ender's fixation on the Giant's Drink challenge could come off as disturbing, since most children would simply dismiss the challenge as unwinnable and move on to another part of the game. Presented as one level in a linear game, Ender's solution (murdering the Giant) becomes the obvious one, his persistence just makes him look like a Determinator, and the grown-ups' horror upon seeing Ender Taking a Third Option looking like they are clueless about how game programming works and/or didn't bothered to call the game's developer to see if that was even possible (the book also mentions something about the game being self-procedurally generating (which is why there's a big surprise about seeing artificial copies of Peter and Valentine Wiggin in the game — the computer was just trying to put something there because nobody had ever beaten the Drink puzzle ever before and there was no "standard" content as a result, so the game mined Ender's psych profile), but this explanation doesn't appears on the movie either — the copies are just... there).
• Happens in The Remake of The Haunting (1999). After Eleanor has been thrown out of bed, she asks, "Who's holding my hand?" In the original movie, this was spoken at the end of a rather tense scene in which Eleanor is convinced that Theo is holding her hand. However, it is revealed a moment later than Theo is on the other side of the room, and that no one was holding her hand. It is used out of context and without explanation in the remake, as there is no one in the room with Eleanor, nor did she imply at any point that someone was holding her hand before she asked the question.
• The Hitchhiker's Guide to the Galaxy (2005) has Ford approaching Arthur with a shopping trolley filled with cans of beer and packets of peanuts. In the book he explains that these are necessary for combatting Teleportation Sickness but not here. With teleportation not being mentioned, we also aren't told how Arthur and Ford got on board the Vogon ship.
• Hombre: In the movie, the bandits who rob the stagecoach know that Mr. Favor, the Indian agent who is one of the passengers, is a crook who has been embezzling from the funds he is supposed to be using to feed the Apache on the reservation. How do they know this? The movie doesn't explain but the source novel by Elmore Leonard does, saying that one of the bandits used to work for the Bureau of Indian Affairs, procuring beef for the reservation, and found out that Favor was skimming off funds.
• The Hunger Games: In the movie, we never find out the symbolic significance of the mockingjay, nor what the Muttations are made out of (in the book, it appeared to be dead tributes mixed with wolf.)
  • The movie also never explains why the female Tribute from District 5 is called Foxface. In the book, it's a nickname Katniss assigns to the girl (due to her sly, fox-like appearance) because she doesn't know her name. In the movie characters just call her that, making it seem like her parents named her that for some reason.
• The Hunt for Red October: In the book, Ramius blames the Soviet state for his wife's death due to a botched surgery (caused by a combination of poor-quality medicine and the incompetence of a drunk doctor who avoids any prosecution because he's politically well-connected) as well as the state's prohibition on religion denying him the means to assuage his grief. In the film, Jack only says that Ramius is defecting on the anniversary of his wife's death, without giving any explanation for why his wife's death triggered such an action.
• The live action adaptation of Jo Jos Bizarre Adventure Diamond Is Unbreakable removes any reference to DIO or the events of JoJo's Bizarre Adventure: Stardust Crusaders, leaving certain aspects of the backstory unexplained.
• John Carter: how quickly John learns Barsoomian. The book states that all Barsoomians have some Psychic Powers. The only explanation for this in the film is that Sola is speaking to him in the "voice of Barsoom."
• Jurassic Park
  • The movie is occasionally criticized for the film claiming its moral is about the unpredictability of nature, when it was really all the programmer Nedry's fault. The book covers this by showing evidence from the park's own data that the populations were indeed out of control. Nedry wasn't the sole cause of the collapse, but he was the final crack to the foundation.
  • The famous sick-triceratops scene also reproduces enough information from the book to infer, if you've read it, that some of the dinosaurs are eating toxic plants, despite the efforts of the park to manage the park's flora. However, the lysine contingency is mentioned without reference to the trouble it ends up causing in the book.
  • The T-rex only being able to see things that were moving was also in the book, but there it was shown to be a result of the dinosaurs' impure genetic makeup, which resulted in various health issues such as poor vision. In the movie, Grant immediately deduces that it can't see them if they're standing still, and it's treated as an in-universe paleontology fact.
• Zack Snyder's Justice League: The lines of the "reactionary terrorists" Wonder Woman fights are changed, omitting mention of them blaming the Kryptonian attacks as retribution against modern technology, making them more like Terrorists Without a Cause now.
• The League of Extraordinary Gentlemen:
  • The movie keeps the comic book's dramatic revelation that "M" is Professor James Moriarty, but it never actually explains how a simple mathematics professor—who's also a notorious criminal mastermind—came to be the head of British Intelligence. The comic book explains that British Intelligence recruited him as an informant years before his confrontation with Sherlock Holmes, allowing him to rise up the ranks of the service until he became the powerful "M".
  • Unlike the movie, the comic book makes it clear from the beginning that it takes place in a world where all fiction is true. Among other things, this means that Sherlock Holmes is a very real world-renowned celebrity whose apparent death made major headlines. Therefore, it's a bit more understandable that Quatermain instantly knows who Moriarty is upon seeing his face.
• Early in The Lightning Thief, it's mentioned that Percy's sword, Riptide, is enchanted to always return to his pocket in the event that he drops or loses it, an explanation that was left out of the two film adaptations. However, the second film still includes a moment where, after being captured by Luke, he works the pen out of his pocket and uses it to escape his bonds, making it seem as though Luke tied him up without disarming him.
• In A Little Princess (1995), Sara wakes up to find her attic room filled with food, clothing and other luxuries. In the book, these things were brought to her in secret over a number of weeks by Ram Dass, the Indian man living next door, while she slept. In the film, they're just there with no explanation. Ram Dass is however implied to be magical in some way.
• The largely unexplained backstory to The Lord of the Rings leaves quite a few of these.
  • The issue of Aragorn as heir to the throne of Gondor. If Boromir can recognise the heir of Isildur simply from the name 'Aragorn', then why isn't he king already? In the books, the issue is far more complicated; while Aragorn is the only surviving heir, he's only distantly related to the old Kings of Gondor, and he also comes from a line that had previously been excluded from the Gondorian succession. In fact, he's technically the heir of Arnor, Gondor's northern counterpart that fell many centuries ago, which is only obliquely mentioned or implied a few times in the films. Gondor's line of kings actually descends from Anárion, Isildur's brother—meaning that Aragorn's claim to the throne is actually based on a lineage that split off three thousand years ago. (Arnor's last king, Arvedui, did have a valid claim on the throne due to having married the crown princess Fíriel, but his claim was rejected due to Arnor's dire state at the time.) The movies explained this as Aragorn himself being reluctant to become king, for fear of falling to petty evil the same way his ancestor Isildur did.
  • For that matter, very little about Sauron is ever explained, leaving casual viewers who haven't read the books to wonder who (and what) he actually is, and how he became so dangerously powerful. In a nutshell: he's one of several lesser deities called Ainur (specifically, a lesser order of Ainur called Maiar) who serve Middle Earth's supreme creator god Eru Ilúvatar. Long before the events of the story, he went rogue and joined another rogue Ainu, a Vala called Melkor (aka "Morgoth") as his right-hand man, and later took up Morgoth's cause after he was defeated and exiled in his attempt to destroy the world. In other words: he's a Fallen Angel in the vein of Lucifer. Admittedly, almost all of this is in The Silmarillion: The Lord of the Rings itself is about as vague on Sauron's nature as the films.
  • In the first book, Gandalf stops at Edoras before going to Rivendell — and learns that Grima Wormtongue has already begun poisoning Theoden's mind. He stops back again before his reunion with Aragorn, Legolas, and Gimli, giving him a further sense of the extent of the damage. This is left out of the film, so it's up in the air how Gandalf is so up to date on what's happening in Rohan.
  • In the book, Bill the Pony is much more fleshed out as a character. The Hobbits buy him (for three times his value) after their own horses are set free while they're staying in Bree. His poor health improves in Rivendell, and when the kraken-like creature in the lake outside Moria attacks, Sam thinks Bill is killed by it, and grieves for him. In the movie, Sam sets Bill free before they get to Moria, and appears like he was just really attached to the animal for no real reason.
  • In both versions, Frodo attempts to share his lembas with Gollum, but Gollum immediately spits it out in disgust and explains that he can't eat elf food. It's not really explained in the films how Gollum is familiar with the taste of elven cooking, but in the books, Gollum is said to have been held captive in Mirkwood for a while, with him escaping shortly before the events of the story (in fact, Legolas's original reason for arriving at Rivendell was to inform Elrond and company of this fact).
  • In both versions, Gandalf demonstrates a deep knowledge of Gollum's history, including the fact that he was once a hobbit and that he was tortured by Sauron until he gave up what little information he knew. The film doesn't really explain how Gandalf knows this, but in the book, it's elaborated on that Aragorn (at Gandalf's request) had captured Gollum some time after he was set free, which allowed Gandalf to question him and fully confirm most of his suspicions. The film also leaves out how Frodo knows Gollum's original name, though the answer ("Gandalf told him") could easily be true in either version.
  • The films' prologue briefly explains the story of the 19 rings that were forged alongside the One Ring (three for the Elves, seven for the Dwarves, nine for the Men); while we're told that the nine human ring-bearers became the Nazgûl (Ringwraiths) after being corrupted by their rings, audiences who haven't read the books are left to wonder what happened to the other ten. The books explain that the Dwarves' seven rings were lost after their kingdoms were consumed by dragons, while Gandalf, Elrond, and Galadriel still have the Elves' three rings.^note  Gandalf was given the ring Narya by the Elf lord Círdan, Elrond inherited the ring Vilya from the Elf lord Gil-galad after his death, and Galadriel has carried the ring Nenya since it was forged. Extra-attentive viewers might notice those three characters wearing rings that resemble the ones donned by the Elves in the prologue, but might wonder why they're able to freely wear them without being corrupted. The answer is that the Three are a separate class of rings that were forged by the Elf smith Celebrimbor rather than by Sauron, and therefore lacked the inherently wicked nature of the Seven and the Nine (though they were still tied to the One, and could be corrupted if Sauron ever got it back).
  • The films don't really elaborate on why the way to get through the Doors of Durin and into Moria is simply to say the elvish word for "friend", other than Frodo referring to it as a "riddle" (which it isn't, really; it's more of a trick question that Gandalf had misinterpreted and was overthinking). In the books, this is elaborated on a little more: the Doors of Durin were created in a time of great peace, and therefore simply naming yourself to be a friend was enough to be allowed in. The password is in an elvish language (specifically, Sindarin) rather than the dwarvish Khuzdul because at the time, the dwarves had a close friendship with the elves living nearby—in fact, a line left out of the films claims that the Doors were created by a collaboration between an elf and a dwarf. Funnily, this was something the far more truncated Bakshi version managed to touch on.
    Legolas: So, all you had to do was say, "friend," and enter.
    Gimli: Those were happier times.
  • In both versions, the major conflict to Arwen's character is that she has the choice to become a human, and therefore mortal, or stay an elf and retain her eternal life. In the film, why Arwen has this ability is not explained, and most viewers would probably assume it to simply be an ability elves have in general. In the books, this is because Arwen is partially human, being descended from Tuor and Beren, and therefore the choice is basically whether to embrace her human heritage. Her father Elrond had the same choice, but chose to stay an elf, which goes a long way to explain his apprehensiveness at the idea (though he is far less bitter towards humanity in the book).
• The Martian: A couple of examples of this trope create minor Fridge Logic moments for anyone who hasn't read the book.
  • Mark Watney never makes any attempt to search for the communications antenna that was torn away in the severe wind-storm that got him stranded on Mars in the first place. This is never touched on in dialogue, but in his first log entry in the book he rules out the idea as impractical: Not only could it have been blown anywhere within a search area of several square kilometres but it's almost certainly completely buried in sand. And it's a line-of-sight microwave dish, not something he could jury-rig a substitute for with spare electrical cable.
  • Some people also noticed that living on nothing but potatoes would leave Mark dead from various vitamin deficiencies long before he could be rescued. This is something he brings up when planning the improvised potato farm: The food NASA sent along on the mission was chosen to be calorie-dense and shelf-stable first, nutritionally balanced second, so their supplies also included an abundance of multivitamin tablets.
• Once Upon a Time (2017) leaves out so much of the source novel, To the Sky Kingdom, that you'd have to either read the novel or watch the more faithful adaptation Ten Miles of Peach Blossoms just to understand what's happening. Among many other things, the film doesn't explain who Mo Yuan is, why Bai Qian keeps his body in a block of ice, or why Qing Cang was imprisoned in the bell.
• In the movie version of Perfect Pie, Marie refuses to go swimming. In the play, this is because she’s been prone unpredictable seizures ever since she was a child and she’s afraid that she’ll have one while swimming and drown. In the movie, this trait was moved to her friend Patsy, leaving Marie’s fear of swimming unexplained.
• Presumed Innocent: Two examples. A reference is made to the "Night Saints", with both Sabich and Lipranzer then interrogating a man who is one. It isn't explained who they are, nor what connection Sabich has with them, while in the book it's said they were a street gang he broke up with a successful prosecution. They also identify Larren Little due to the man's reference toward him as "Judge Motherfucker". Again, this isn't explained. The book related that he got this nickname due to a joke in court once claiming that "motherfucker" was a term of endearment among black people. A viewer who hasn't read the book will likely be left no idea what either of these means.
• In the film of The Princess Bride, Buttercup is somewhat confusingly presented to the populace as a princess when she's betrothed, but not yet married, to Prince Humperdinck. The book explains that she was declared princess-by-fiat of some little backwater principality just so that Humperdinck wouldn't be marrying a commoner.
• A Scanner Darkly:
  • In the novel, Bob and friends freak out and get angry because Barris brings home an 18-speed bike that he bought from someone, but Luckman only counts 9 gears (6 in back, 3 in front), leading them to think that Barris got ripped off. In the book, this scene is intended to show that Bob's cognitive faculties are being eroded by his drug use while undercover, since he didn't realize that his friends were wrong about the bike: they were adding the sets of gears instead of multiplying them, which is how multiple-speed bikes work (each gear in front connects to each gear in back). The movie keeps the scene where Bob's superiors explain that they're pulling him out due to his drug use affecting his brain, but they don't explain that they were tipped off by his reaction to the argument about the bike, leaving the scene somewhat bizarre and unexplained.
  • In a scene where the characters are riding in a tow truck after their car breaks down on the highway, Luckman blurts out "If I'd known it was harmless, I'd have killed it myself!" In the book, the statement is explained via flashback as an in-joke among the group about how different classes of people view the world differently: one of their old housemates was a spoiled rich girl who once freaked out when she saw a bug climbing on the wall, and asked the others to kill it; when they explained that the bug was harmless, she replied "If I'd known it was harmless, I'd have killed it myself!".
• Scott Pilgrim vs. The World includes the Subspace Doors from the graphic novels, but never explains what they are, despite being used during pretty important scenes. It isn't hugely jarring though, considering all the other nonsensical video game tropes and references that are just naturally part of story.
• She (1965): The novel has a complicated beginning describing how Horace Holly gets drawn into the Vincey family quest to find a lost city in Darkest Africa, and the months of preparation he and Leo Vincey take before setting out for Africa. The 1965 movie drops all of that and opens with Holly and Vincey, army buddies, already in Africa on unrelated business when the opportunity to search for a lost city is presented to them. As a result, it's just a convenient coincidence that Holly happens to know a lot of useful stuff about antiquity.
• Stanley Kubrick's The Shining turns some plotlines from the book—mentions of "Tony", the dead lady in the bathtub, and the fellow in the dog costume that Horace Derwent debases—into bizarre one-off scenes. He also revised the story's climax, cutting out the exploding boiler, but still took care to show the boiler in a couple of scenes. It's fairly likely that the absence of explanation for most of these elements was deliberate, though, since the lack of exposition adds to the film's mystery and ability to shock the audience.
• The Mystery Science Theater 3000 episode version of Space Mutiny cuts out a small but important bit of dialogue where Kalgan explains the whole reason for wanting to mutiny and go to Corona Borealis is to sell the rest of the crew as slave to the pirates who live there. This has the unfortunate effect of making the mutineers Unintentionally Sympathetic, as without this explanation it seems like they just want to go live on Corona Borealis, and the people in charge of the Southern Sun are forcing them to stay just because they said so.
• In Spider-Man 3:
  • Peter gains his infamous black symbiote but other than adapting to his costume and making him more hostile, the nature of the symbiote is not explained that much. When it comes time for Eddie Brock to put on the costume, there is no explanation given as to why he now has spider-powers and the audience is left to assume based on the comics.
  • The movie also adapts the scene from the comics where Peter removes the symbiote in a church bell tower. In the comics, Peter did so because he knew from past experience about the symbiote's weakness to sonic vibrations and had no choice but to go to the tower. However, Peter doesn't figure out the symbiote's weakness until well-after he went to the bell tower - meaning he had no real reason to go there other than because of the comics. (The symbiote's weakness is clearly hinted at during this scene for viewers' benefit, but Peter doesn't put the pieces together until his final battle with Venom - which is several scenes after the fact.)
• The film adaptation of Timeline foregoes the language difficulties presented in the book. In the book, the medieval characters speak a mixture of Middle English, Old French, Occitan and Latin, with the time travelers needing earpiece translators to understand them while they themselves struggle to be understood. In the film, the medievals simply speak modern English and French and have no trouble understanding the time travelers..
• In Twilight:
  • Bella runs into some nasty characters who are going to hurt and possibly rape her. In the book, she has gotten lost by this point and does not know where to run, so prepares to scream and fight. It also says that if she tried to run, she would probably trip over her own feet. In the movie, she's still clumsy, but not that clumsy, and is still in sight of a reputable book store. Why she doesn't just turn around is not addressed.
  • Also in the manga: in the book and movie, it's made pretty apparent that Edward is bothered by how Bella smells in their first biology class. In the manga, we get a few panels of him glaring pissily at her, which doesn't really indicate her smell being what's causing the issues and which leaves the panel where she sniffs her hair making her look like she has some nervous tic.
• In V for Vendetta, Britain’s secret police are called "fingermen", which might strike some people as an odd name for a scary group of fascist enforcers. The movie never explains that the name is derived from the secret police force being collectively known as "The Finger", and there's no mention of the other government agencies following the same Theme Naming (with the visual surveillance department being called "The Eye", the audio surveillance department being "The Ear", the criminal investigation force being "The Nose", and the government propaganda office being "The Mouth").
• In Vampire Academy, Lissa is tortured by an blind user to prevent her from using compulsion on him. However, this review points out that why couldn't she heal his blindness just so she could compel him? This is because her hands are tied down, and her healing power only works through physical contact such as touch, which is outright explained in the Book but only hinted at in the Movie.
• Watchmen:
  • The movie never explains how the distinctive blots on Rorschach's mask constantly shift and move, leaving some viewers to wonder how a dirt-poor street vigilante got his hands on such a seemingly advanced piece of synthetic fabric (especially since the story takes place in the 1980s, when such materials weren't widely available). The book explains that it's one of many synthetic materials developed through Doctor Manhattan's experiments with physical matter, and Rorschach acquired it when he was working in a garment shop before becoming a crime-fighter.^note  The fabric was originally intended to be used in a dress, but the buyer returned it because she didn't like how it looked. Rorschach claims that the buyer was none other than Kitty Genovese, whose brutal murder partly inspired his black-and-white view of morality. The mask's pattern is actually a mixture of two viscous fluids (one black, one white) trapped between sheets of transparent fabric, which shift and form symmetrical patterns in response to heat and pressure.
  • The movie leaves it somewhat ambiguous why Laurie decides to move in with Dan so soon after Doctor Manhattan leaves Earth, seemingly implying that she's just lonely and seeking solace. The book explains that she was previously kept on retainer by Doctor Manhattan's handlers in the military, who encouraged their relationship in hopes that she could keep him from becoming too detached from humanity. After Manhattan leaves, the military cuts off her expense account and kicks her out of Rockefeller Military Research Center, leaving her jobless and homeless.^note  The Director's Cut includes an additional scene where Laurie flees the base after two soldiers attempt to interrogate her, possibly implying that she also fears for her safety.
  • The movie explains very little about Edgar Jacobi (aka "Moloch the Mystic") beyond vaguely implying the he's a former enemy of Rorschach and company. In the book, Hollis Mason's in-universe biography Under the Hood explains that he's a former crime lord who got his start as a stage magician, and eventually got rich by running vice operations out of the nightclubs where he performed his magic act.
• The Wizard of Oz:
  • The 1939 film version portrays the Winged Monkeys as the unquestioningly loyal servants of the Wicked Witch of the West, but never wastes any time explaining how they came into her service (the fact that they're her Mooks is presumably enough explanation for most people). But L. Frank Baum's original novel, The Wonderful Wizard of Oz, specifically explained that the Monkeys were bound to obey the Witch's commands because she possessed a magical golden cap that gave her power over them. It also explained that they weren't technically her Mooks, as they were only required to obey three commands from the bearer of the golden cap; the Witch used up her last command when she had the Monkeys capture Dorothy and her friends. Since the whole Golden Cap thing is largely a Chekhov's Gun that pays off in a story arc that was excluded from the film, it's not really needed in the film anyway.
  • The significance of various colors was always a central part of the Oz mythos in the books, as Oz was portrayed as a society built around the celebration of color and beauty. This is why some of the most iconic elements of the story are instantly identifiable by their color: Dorothy wears a blue gingham dress and red ruby slippers^note Though they were silver shoes in the book, she travels along a yellow brick road to reach a city of green emeralds, there's a deliberate shot of a red brick road that leads in the opposite direction from the yellow brick road, and scenes in Oz are filmed in color while scenes in Kansas are filmed in monochrome. The movie retains the original book's striking use of color, but it generally doesn't explain why the various colors are significant. In the book, the Munchkins instantly trust Dorothy because she wears blue, which is the color of Munchkinland; various characters assume that Dorothy is a witch because her dress is patterned with white checks, and only sorceresses wear white; the Yellow Brick Road is yellow because it leads to Winkie Country (the land west of Munchkinland ruled by the Wicked Witch), whose color is yellow; the Red Brick Road in Munchkinland leads to Quadling Country, whose color is red; and the Emerald City is green because it's an independent capital city that lies at the center of the four regions of Oz, and thus has its own color.
  • Some viewers might wonder why everyone in Oz seems to accept the Wizard as the ruler of the Emerald City so casually, since he's an outsider who wasn't even born in Oz, and there must have been someone else ruling the Emerald City before he dropped in. For that matter, his departure can cause a bit of Fridge Horror when you think about the fact that he's essentially leaving a power vacuum in the capital of Oz, with no apparent plans to appoint a successor. The novel (and its sequels) explained both points: he named the Scarecrow as his successor before he left Oz, and it was later revealed that the previous ruler of Oz was a benevolent king named Pastoria who died shortly before the Wizard arrived, while his daughter Princess Ozma mysteriously vanished soon afterward. ^note  The Twist Ending of The Marvelous Land of Oz reveals that Ozma was kidnapped by the Wizard and given to an evil witch named Mombi, who transformed her into a young boy named "Tip" to hide her identity. Once Tip is unmasked as Ozma and turned back, she assumes the throne in the Emerald City again.
  • The Witch’s weakness against water was another example of this: in the book, it’s exposited early on that the two Wicked Witches are so old and shriveled that they’ve essentially been mummified, with all the fluid in their bodies having dried up long ago. This was why the Witch of the East disappeared after Dorothy’s house fell on her — her body literally crumbled away into dust — and why a pail of water caused the Witch of the West to melt away. Whereas in the movies, it’s just a weird, unexplained weakness of hers.
  • The movie omits the Tin Man's backstory, but vaguely implies that he's an artificial human who was magically made sentient. The book explains that he was once a perfectly normal human woodcutter, but lost all his limbs (and his head and torso) after the Wicked Witch of the East bewitched his axe to slip and cut him, forcing him to replace all of his body parts with tin. It also explains that he doesn't have a heart because the Witch used her magic to steal it, hoping to sabotage his relationship with the Munchkin girl who he planned to marry.
• The novel Who Censored Roger Rabbit? (which Who Framed Roger Rabbit is based on) has a Twist Ending that explains the seemingly implausible pairing of Jessica and Roger: the MacGuffin is actually a magic lamp containing a genie, which granted Roger two wishes—one of which was to marry Jessica. As the plot of the novel is completely different from the film, however, the movie's version of the Jessica/Roger relationship is simply treated as some strange, funny case of Deliberate Values Dissonance between humans and Toons (Toons value humor more than physical attractiveness, so Roger is considered one of most desirable people in Toontown).
• X-Men Film Series:
  • The original X-Men trilogy might leave some viewers wondering how Professor Xavier can afford a sprawling Westchester mansion with its own stealth jet—since he has no apparent source of income, and doesn't appear to charge his students tuition or board. The comics explain that he's the heir to a vast family fortune, and the mansion is an ancestral manor that's been in his family for five generations.^note  May overlap with Adaptation-Induced Plot Hole, since the movies' version of Xavier appears to be British, yet somehow apparently inherited a mansion in upstate New York.
  • The movies' portrayal of Cyclops keeps most of his notable traits from the comics, but they omit his backstory, leaving most of those traits unexplained. In particular: he's shown to be much closer to Professor Xavier than the other X-Men, and he can't control his optic blasts (forcing him to wear his ruby quartz glasses at all times). The comics explain that he lost his parents in a plane crash when he was a child, and the Professor is the closest thing he has to a father; he suffered significant head trauma in the crash, which left him permanently unable to control his powers when they manifested.
  • The movies are deliberately vague about the origins of the Mutant race, but they generally imply that Mutants are a perfectly natural evolutionary offshoot of humanity. The comics explain that Mutants exist as a result of the Celestials implanting the X-gene into the DNA of a few early humans, eventually causing their descendants to develop bizarre mutations; this is generally used as a cozy Hand Wave for why Mutants' powers vary so widely, and why some of them have abilities that appear more magical than biological.
  • X-Men: First Class leaves it ambiguous how Sebastian Shaw and the Hellfire Club have enough money and influence to drive the nations of the world to the brink of nuclear war. The comics explain that the Hellfire Club is much older than Shaw himself; it's a centuries-old fraternal organization that was originally a secret society for the wealthy and elite of the world, but Sebastian Shaw and Emma Frost led a coup from within and seized full control of the group's accumulated riches.
  • X-Men: Apocalypse doesn't waste any time explaining how Ororo Munroe wound up living in Egypt, despite being (by all appearances) of sub-Saharan African descent. The X-Men comics explain that she was born in Harlem to an African-American father and a Kenyan mother, but moved to Cairo as a child.

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