Hermione's subplot could be interpreted as, "Doing well in school is great, but your mental health comes first. No matter how smart you are, you can still bite off more than you can chew, so if school is putting a strain on your well-being, it's ok to dial back a bit."
The incident with Lupin before the climax has the lesson of "Always remember to take your meds."
Sir Cadogan, the portrait that takes over guarding Gryffindor Tower for The Fat Lady after she's attacked by Sirius Black, and whose work style involves setting "ridiculously complicated" passwords, and changing them at least twice a day. Is he stark raving mad, or Properly Paranoid taken up to eleven? The fact that he had no problem with a student writing them all down on a piece of paper that anyone could read seems to imply the latter, however.
Was Professor McGonagall not allowing Harry to visit Hogsmeade on weekends without a signed permission form a case of her just sticking to the rules with no exceptions? Or was she just using it as an excuse to keep Harry in the castle so that the staff and security could keep him safe from Sirius Black?
Snape's behaviour in this novel, where he's at his most emotional and unhinged has drawn a lot of views. Notably fans invoke information from later series to explain why he was so personally angry at Lupin. Others however note that his taunting at Harry by using Lily's own insults about James to the latter, and then having the latter remind him, much as Lily did in The Prince's Tale that James did save his life, and repeating the same conversation, while in the finale shouting at Harry that James deserved to die because he was too arrogant to distrust Sirius is more or less him vicariously trying to argue that Lily was a fool for choosing James and wondering What Does She See in Him?.
In terms of his behaviour towards Black in the Shrieking Shack, did he want revenge because he believed Black was the one who sold out Lily to Voldemort? Or was he one of the Death Eaters who knew Pettigrew was the actual spy, but still blamed Black for her death because he decided not to be the Secret Keeper himself?
Was Fudge seriously concerned about Harry's safety because he is a 13-year-old boy that, so far as Fudge knew, a mass murderer wanted to kill, or more worried about the political fallout if The Boy Who Lived had died at the hands of a follower of Voldemort that escaped Azkaban on his watch?
Was Sirius actually trying to get Snape killed with his Deadly Prank? Or was it a case of Didn't Think This Through on his part, with Sirius giving Snape the information to taunt him and not believing that he would have the nerve to act on it?
Did James save Snape from being attacked by Lupin in his werewolf form when they were at school because he felt Sirius tricking Snape into encountering him was going too far? Or was James more concerned about Lupin possibly having to live with the guilt of killing a classmate and only saved Snape to spare his friend from such a scenario?
In a larger sense, the entire ending. Harry and Hermione manage to save Buckbeak, Sirius, and Harry, get out of trouble with the staff thanks to Dumbledore placing his faith in their story about Sirius, and Harry's foul mood caused by Lupin resigning is finally dispelled by a letter from Sirius explaining he won't have to deal with Dementors around Hogwarts in the next book, a signed Hogwarts permission slip, and the ability to scare the Dursleys out of abusing him too badly with the knowledge that his godfather is wanted for murder.
Crosses the Line Twice: Oliver Wood finds out that Harry received a Firebolt anonymously, and it was confiscated by the teachers. He says he'll talk to Professor McGonagall and convince her to give back the broom. A few weeks later, he goes to Harry and sheepishly said that their Head of House refused. Apparently Wood said that he didn't care if the broom threw off Harry as long as he caught the Snitch, and Professor McGonagall got "shirty" with him.
Crazy Is Cool: The Knight Bus, a triple decker bus that travels at amazingly high speeds, regardless of Muggle traffic laws, with contraptions such as making the bus skinny to squeeze between other vehicles.
Draco in Leather Pants: Malfoy has gotten a lot of sympathy from some fans for his injury; they see his parents' complaints about Buckbeak being justified. This completely ignores that not only was he clearly faking the severity of his injury, but that he explicitly ignored Hagrid's instructions to the class to not insult the hippogriffs.
Ending Fatigue: Not too bad, but off to see Buckbeak get executed—diverted to shrieking shack, long Plot Dump, Werewolf ensues, time turner, going back though the evening and THEN it's over. Depending on your point of view, it either is a tense, fast-paced moment filled with story revelations or feels like too much got crammed in at the end and these should have been sprinkled throughout.
Franchise Original Sin: This book introduces time travel to the Harry Potter universe. While it is used here in a relatively restrained way to tie up the plot, it would later be used in a much more drastic and maligned way in Harry Potter and the Cursed Child.
Growing the Beard: Many fans believe that this is the turning point for the series as a whole, citing the encounter at the Shrieking Shack, the darker emotions and actual feelings of loss Harry feels about his family (that had not been really explored in the previous books) and of course the Bittersweet Ending. Sirius is proven innocent to Harry and Dumbledore but remains on the run alongside Buckbeak, and Lupin has to quit, while Harry worries about Trelawney's prophecy and the consequences of sparing Wormtail potentially bringing Voldemort back. Compared to the out-and-out positive victories in the first two books, it was bleaker and prepared for the gradual darkening of the remaining books.
At one point in Harry Potter and the Philosopher's Stone, Scabbers bit Goyle on the knuckle (which was even referenced by Fred and George Weasley in Prisoner of Azkaban). Here, it's revealed that Scabbers was actually Peter Pettigrew, who was the true person responsible for leaking Lily and James Potter's location to Lord Voldemort and thus their deaths. Coupled with the later revelation in Goblet of Fire that Goyle's father was most likely one of Pettigrew's comrades among the Death Eaters, it becomes somewhat disturbing.
Ron carrying him around in his pocket and Scabbers even falling asleep on Harry's bed at one point in Philosopher's Stone. Counts in-universe too as when Pettigrew tries to plead with Ron for mercy, Ron (with appropriate anger and disgust) points out he let the rat sleep on his bed.
Kindly Diagon Alley merchant Florean Fortescue helping Harry with his history homework feels grimmer after he is kidnapped by Death Eaters in Book 6. Word of God indicates it was because his vast historical knowledge had a clue about the Elder Wand and that he was killed after being interrogated.
This may overlap with Heartwarming, but in this book, Oliver Wood finally fulfills his dream of winning the Hogwarts Quidditch Cup. In the following books, the Cup is cancelled and replaced by the Triwizard Tournament, Umbridge disbands all clubs, teams, and student organizations and tries to prevent the Gryffindor team from reforming, and she gives Harry, Fred, and George a lifetime ban from Quidditch, and once that's undone, Harry gets his skull accidentally cracked by a teammate and has detention during the final, forcing Ginny to sub for him, and finally, not only does Harry drop out of Hogwarts to go Horcrux hunting, but Quidditch at Hogwarts is never mentioned, and it's entirely likely Voldemort or Snape had the Cup cancelled again.
After finally proving his innocence and leaving the Shrieking Shack, Sirius Black offers to have Harry move in with him, which Harry is naturally over the moon about. He even tries to use this offer to cast a Patronus Charm the first time round. Come book five and, all told, Harry got to spend about 4 and a half weeks living with Sirius, during which time everyone was worried about Harry's Hogwarts expulsion hearing, the return of Lord Voldemort, the Order of the Phoenix trying to Lock the children Out Of The Loop and, perhaps worst of all, Kreacher and Sirius' mother's portrait being unbelievably racist towards everyone around him.
Madam Pomfrey checks over Harry when McGonagall asks, following the Dementors searching the train; she nods in approval when Harry reveals that Lupin gave everyone chocolate. Lupin later reveals that Madam Pomfrey personally escorted him to the Whomping Willow before every full moon. Looks like he learned wizard medical care from the best.
In the penultimate chapter of the book, when Harry first sees his corporeal stag Patronus, he mistakes it for a horse. In the film adaptation of Order of the Phoenix, his future wife, Ginny, masters a corporeal Patronus, which was later confirmed as canon by Word of God and Pottermore, as stated here. What's her Patronus? A horse.
Early on, Harry overhears a Muggle news report about Sirius Black's escape from Azkaban, (later revealed to be that Fudge told his Muggle counterpart about it to try better to catch him) but the report of course omits that Sirius is a wizard and which prison he actually escaped from to preserve The Masquerade, which Vernon gets indignant over since if they don't know where he escaped from then for all they know he could be walking up Privet Drive right that very second. The Reveal that Sirius and the Grim are one and the same means that, in fact, he was headed for Privet Drive. Luckily, Sirius is a good guy and was only going there to try to protect Harry.
The part where Snape gets insulted by the Marauder's Map after Pottermore revealed that it was designed to do that to Snape and only Snape, not just anyone who tried to read it without the password.
In the novel, Hagrid expresses worry that Buckbeak might have encountered werewolf!Lupin in his escape from Hogwarts. As the movie illustrates, Hagrid need not have worried for Beaky's welfare in such a fight.
While discussing Sirius Black, Hagrid says that if he had found Sirius before Pettigrew did he would have 'ripped him limb from limb'. Fudge dismisses the idea saying only a squad of Hit Wizards would have stood a chance against him. Two books later we see a fight between Hagrid and a squad of Aurors. Hagrid wins. Easily.
In the first chapter, Hermione is vacationing in France and mentions in a letter that, "there's some interesting local history of witchcraft here." Perhaps she was studying certain events that took place in Paris in 1927.
Never Live It Down: Among a lot of fans, Snape never quite recovers from this book, even after re-reading the series with all his motivations revealed. He's wildly unprofessional, sadistically and openly cruel even to students like Neville to a level that would have gotten any teacher fired from a Muggle school, is willing to send Sirius and Lupin to the Dementor's Kiss even after Sirius makes clear his intentions of turning himself in to Dumbledore, and then outed Remus Lupin as a werewolf publicly. Even the revelation from the later books about Sirius bullying Snape when they were Hogwarts students, and Snape being a spy for the Order, does nothing to vindicate his conduct here, since his incompetence, i.e. neglecting to bring or mention the Wolfsbane Potion to Remus after entering the Shack, plays a major albeit unintentional part in letting Peter Pettigrew escape, a detail that slipped him since he wanted to get back at Sirius and Lupin, and causing a bunch of other deaths that otherwise wouldn't have happened. While the film version of Snape is generally less cruel and bullying than in the book anyway, The Prisoner Of Azkaban's adaptation notably tones down his behaviour more than any other film in the series does.
One-Scene Wonder: Aunt Marge only appears in one chapter (which has her name on it), but still manages to be among the more despicable characters in the series, perhaps even more so than her brother Vernon.
The quidditch match against Slytherin, which is essentially just what was supposed to be the Grand Finale of the quidditch scenes at Hogwarts, and where the team finally wins the cup.
To an extent, the one against Ravenclaw, but it has a little more plot-relevance, as it introduces Cho and is where Harry first manages to cast a really successful Patronus.
Hagrid calls out Ron for valuing his pet over his friendship with Hermione when it seems that Crookshanks has eaten Scabbers. The narrative reveals that Crookshanks knew that Scabbers wasn't a real rat but didn't tell anyone besides Sirius, despite the fact that the Gryffindor Head of House is also an Animagus; Pettigrew took the opportunity to fake his death. Here is the thing: Crookshanks's first encounter with Ron was attacking him and going for Scabbers. From the pet witch's reaction — "NO CROOKSHANKS NO!" it's reasonable for Ron to believe that Crookshanks is a bit trigger-happy and he ends up being right that the cat was aiming for his pet. The other thing is that Hermione for most of the book refuses to do anything about Crookshanks attacking Scabbers, defending his violent behaviour as acting like a cat because of Cats Are Mean by nature. While one could attribute it to Hermione being overworked and not thinking things through, it's an insensitive thing to say. Harry acknowledges this because the evidence points to Crookshanks having eaten Scabbers and Hagrid concedes that people can be a bit stupid when it comes to their pets. Ron even says that he'd forgive Hermione if she just apologized rather than acting like "Scabbers was on vacation," because imagine if your pet was seemingly Eaten Alive with his blood left on your bedsheets. Pettigrew faking his death ends up resolving the situation. And indeed, he does forgive her when she finally apologizes tearfully after he promises to help her with Buckbeak's case.
While Draco clearly milks his injury for all it's worth, it still wasn't lost on many readers that Hagrid bringing in a creature that could be set off so easily to a beginners class wasn't exactly the best idea for a teacher. On the other hand, Hagrid at least makes the effort to warn the students that insulting hippogriffs is a bad idea, a warning that Draco chooses to ignore. Draco also makes it clear that he only did it to get Hagrid in trouble, with no regard for his personal well-being.
YMMV tropes present in the film:
Base-Breaking Character: The Shrunken Head on the Knight Bus. Some find him bizarrely out of place and unnecessary, others find him a nice bit of comic relief. It's worth noting that it was approved by J. K. Rowling - who prevented Alfonso Cuarón from inserting a choir of tiny people playing the piano.
Broken Base: Half the fanbase considers this one of the best (if not the best) Harry Potter film in the franchise, or at least when the Harry Potter films started getting good. The other half considers this movie to be one of the worst (if not the worst) Harry Potter film in the franchise. The film was mostly better received by critics than the first two, although it was the first HP film not to get four stars from Roger Ebert. Also, this is J.K. Rowling's favourite film. It generally comes down to either "good scripting" vs. "good cinematography" (with the film lacking in the former and bountiful in the latter), or "Darker and Edgier" vs. "whimsical and fun" (with the film relishing in the former, as opposed to the latter which had endeared audiences to the first two films). Others who read the book also generally have problems with how much stuff was cut from the film in the adaptation process, as it leads to plot or logic holes from how much was cut, as well as cut some of the biggest revelations and moments from the book.
Catharsis Factor: Hermione punching Malfoy is one of the most satisfying scenes in the film.
Instead of being trapped on the ceiling like in the book, Aunt Marge is last seen floating out the house and into the sky. Given what she was saying about her dogs, Harry, James, and especiallyLily, she may have deserved far worse.
Continuity Lock-Out: This was the point when the movies started to get hard to understand for anyone who wasn't already familiar with the books. Most notably: the movie never makes it clear who Padfoot, Wormtail, Moony, and Prongs are, despite later movies operating on the assumption that the viewers all know. Case in point: Voldemort casually addresses Pettigrew as "Wormtail" in the opening of the very next movie, even though it was never explained that he was Wormtail.
Critical Dissonance: The film was adored by critics when it came out, opening to the most critical success any Potter film had seen at that point. On the other side, it left the Potter fanbase fairly polarized. It was also the least successful Potter film at the box office, albeit still incredibly profitable compared to any "normal" blockbuster.
Ensemble Dark Horse: There is a nameless wizard played by Ian Brown who makes a very quick appearance in the Leaky Cauldron, reading A Brief History Of Time and stirring his drink magically without a wand. As wandless magic is something that apparently requires a high degree of skill, and the fact that this wizard is reading a book written by one of Muggle-kind's most prominent physicists when wizards typically disdain Muggle science, a number of fans are convinced that this nameless wizard is secretly one of the most powerful wizards ever depicted in the HP universe due to his open-mindedness regarding what Muggles are capable of and his high degree of skill with magic.
Growing the Beard: According to most professional critics, along with about half of the fans. At the very least, people agreed that the younger actors and actresses were finally fitting snugly into their roles (aside from the Narm mentioned below). What's more is that this was the first film to make deviations from the book in the name of Pragmatic Adaptation, paving the way for the future films to do so (without falling into In Name Only).
Hilarious in Hindsight: Emma Watson would get into astrology in her thirties, and in 2023, she credited her Saturn return for changing her life in an Instagram post. This makes it retroactively ironic that Hermione is the one who doesn't believe in divination.note Although astrology is not portrayed in this film, it is a form of divination, and Professor Trelawney does teach it in the book version of Goblet of Fire.
Improved Second Attempt: It's often felt that the Time Turner reveal comes a little too out of nowhere, with only mild bits of foreshadowing that are easy to miss, and Harry saving his past self casting the Patronus is almost completely out of left field. The film builds up to it more by having Hermione turn up out of nowhere during classes, and adding in more instances of Harry and Hermione's future selves influencing the events of the past to build to that reveal.
Memetic Molester: In the MAD Magazine parody ("Harry Plodder and the Pre-Teen Nerds are Actin' Bad"), when Malfoy gets attacked by Buckbeak, he says he won't describe what he's doing to him with his horse half.
At the very end of the scene where Lupin berates Harry for not turning in the Marauder's Map, there's an obvious (especially so when looking at the lighting) jump to a different take in the middle of a shot. It occurs just after Harry tells Lupin that he thinks the map might not be working since he saw Peter Pettigrew on it.
The final scene of Harry riding his new Firebolt gets a horribly smeared freeze-frame to end the film on. While this was supposedly meant to be an inverse of the effect used with the Dementors feasting on happiness, to show Harry's happiness in contrast to the sadness brought on by the Dementors, the idea does not translate well onscreen.
Many of the film's drastic changes from the book were not welcome to some:
The excision of the explanation of the identities of Moony, Wormtail, Padfoot, and Prongs, which confused many moviegoers who hadn't read the books. Especially since it would have been relatively simple to slip into Lupin's final scene.
Ron losing his Moment of Awesome of standing up for Harry in front of a supposedly-murderous Sirius, with a broken leg, to Hermione, who, unlike Ron, had already had no shortage of moments to shine in the films.
The Dementors are growling, hissing, flying ghouls who, while effective for what they are, are just classic horror-monsters — as opposed to the books' disturbing, otherworldly beings who didn't need to pose any physical threat, or even move at any speed, because the mental effects of their sheer presence was enough to incapacitate their enemies. The changes to their design and behaviour also make them more animalistic, even though they are sentient humanoids in the books — albeit ones much weirder and more threatening than Goblins or Elves.
Then there were the changes compared to the previous two films in the series:
Alfonso Cuarón's complete redesigning of Hogwarts geography, as well as the general shift in tone, with more openly-comedic moments but also a general Darker and Edgier feel that contrasts from the more whimsical tone of the first two films. (This was meant to translate the introduction of darker themes in the books as the series went on, but in the books it was a progressive, creeping growth that you didn't necessarily notice as you went, whereas the transition in the films was more abrupt.) Regardless of the actual tone, the fact that the visuals were literally darker and less colourful was controversial for people who preferred the previous films' brighter and warmer colour-design.
Though a recast was unavoidable due to the death of Richard Harris, the radically different new Dumbledore didn't sit too well with quite a few people. For starters, little effort was made to make Michael Gambon look or act like the Harris portrayal of the first films, even for really basic things like his haircut or trademark gold-rimmed glasses. Indeed, regardless of his acting, Gambon's Dumbledore physically looks less like his book self than Harris's.
YMMV tropes present in the video game:
Annoying Video Game Helper: All three main characters in the console version. While you're wandering around, whoever you aren't playing as at the moment will constantly remind you where you need to be, what you need to be doing, or just drop endless Captain Obvious hints. Especially annoying if you completed a level and choose to explore before moving on to the next, where any of them will constantly talk about wanting to go to bed.
There's also the occasional pop up at the bottom of the screen reminding players they can use the Right Stick to move the camera around which can also get annoying though admittedly not as much.
Anti-Climax Boss: The GBA game's final boss, Draco Malfoy, is literally a reskin of a previous boss fight with Crabbe and Goyle with almost no upgrades. He can be frozen with Petrificus Totalis and can be wailed on with other spells like Flipendo Trio.
Awesome Music: The GBA game's soundtrack is gorgeous through and through, but the standout is the final boss battle theme, feeling suitably intense and ominous, and it really pushes the GBA's soundcard to its limit.
Breather Level: "Buckbeak" in the console versions only has one task: go to Hagrid's Care of Magical Creatures class and play the Hippogriff flight minigame which isn't too hard to do. The level ends when you do good enough in the minigame.
Or perhaps Hilarious in Hindsight, depending on how you feel about Peeves. This is the last Potter video game to feature Peeves before he disappears from the game series. In the PC version, he's the Final Boss, and the following exchange occurs after he's been driven off for good:
Hermione: You don't think we overdid it... making him cry like that? Ron: Don't worry, he'll be back to annoy us again in no time.
Also In the console versions, in the final level (that is basically a free roam level), you can find Peeves at the top of the Grand Staircase who promises the trio he won't give them trouble because he's waiting until next year... which, again, he doesn't return
Peeves: Don't worry. You won't get any trouble from me. Old Peevesey is saving his energy for next year. Then you'll have to watch out!
In the console versions, You can find a Quidditch picture (a screenshot of the first movie actually) in the boys dorm. If it is approached as Ron he'll remember the World Cup is happening next year and England and wishes he could see it. If you've read or seen Goblet of Fire, this line hits differently.
Ron: That reminds me: The Quidditch World Cup is happening in England next year! I really wish I could go and see it...
Narm Charm: In the console versions, whenever you're in a stealth segment involving Snape and he catches you, he starts coughing his lungs out. This is due to a glitch that triggers him to say the wrong line instead of chastising you gor sneaking around. Nonetheless, it is pretty funny to get caught by Snape and hear him hack uncontrollably.
That One Boss: Lupin in the GBA game. It's a very odd fight as Harry and Hermione's spells do almost nothing to him even at level 99, meaning you have to rely on Buckbeak for damage output. Problem is, Lupin is still stronger than him, his attacks can paralyze anyone struck by them, and it's an automatic defeat if his health drops to zero. The game offers no straightforward solutions to this, but the best one is to buy a particular wizard card from Fred and George's shop that can heal party members and to utilize Hermione's abilities to protect and buff the party as much as possible.
They Wasted a Perfectly Good Plot: The time travel element introduced late in the story is already well known, but how the console versions handle it is very barebones: it cuts straight to when Harry and Hermione see themselves on the other side of the lake and when the former saves themselves and Sirius. It would have made this segment interesting if Harry and Hermione had to leave Hogwarts castle and not be seen by anyone and how they managed to save Buckbeak (it was not revealed what the slashing noise was this time).
Underused Game Mechanic: In the console versions, one of Harry's Abilities that Ron or Hermione can't do is climb ropes to reach higher places. Since ropes only appear in two areas in the whole game, you'll forget they even exist shortly after using them.
. What's her Patronus? A horse.