Far more people have seen the (rather faithfully adapted) film than have read the book, which Burgess himself considered one of his minor works (as do most literary critics, since he was a respected author of Lit Fic and a literary critic in his own right), and whose main resentment was that thanks to the film it became one of his Black Sheep Hit.invoked
Most people have never heard the original "Music For the Funeral For Queen Mary".
For some "Singin' in the Rain" is associated with this film, and it still is among a small group of fans, but luckily for Gene Kelly the audience that watches family musicals is always going to be bigger than people who watch Kubrick films.
Did Alex really reform at the end of the novel? Or has he simply grown tired of committing violence himself?
How responsible is Alex for his actions? The way he describes the urge to rape the two ten-year-old girls he comes across, it's implied he acts on uncontrollable urges, but he also willingly drinks spiked milk that makes him more violent. This is probably intended by the writer, as the book deals with the concept of free choice, specifically the choice to be violent, and Burgess himself saw it as a weak satire without stuff thought too much in detail.
There's a reason why being a certain age (usually 18) is a criterion for an antisocial personality disorder diagnosis. As it happens, while teenagers might have the intellectual and physical maturity of adults, they lack the moral and emotional maturity of adults. Alex is simply an extreme case of a teenager lacking these qualities, which he gains through advancing in age and maturity at the end of the novel.
Anvilicious: Most Kubrick films tend not to be so overt in its points and themes but this film has multiple characters blather on in endless dialogues about free will and choice, and unusually so, the protagonist Alex gets a voiceover to explain his thoughts and worldview (Kubrick generally wanted audiences to be detached from the action and not spell things out). The prison chaplain's speech is especially grating not only for its preachiness but it's ineffectiveness (he makes the speech after Alex is submitted to aversion therapy, and not before).
Award Snub: Mr. McDowell ultimately didn't win an award for his performance as Alex. He didn't even get nominated!
Counterpart Comparison: It was released in the same year as Sam Peckinpah's Straw Dogs and in many ways that film is the same theme and plot told from the perspective of the writer Mr. Alexander, with the academic David Sumner becoming dehumanized as he asserts his masculinity by increasingly brutal violence to defend his home. Likewise, where Mrs. Alexander is Stuffed into the Fridge, Susan George's Amy survives the film, tries to deal with the trauma of her violence on her own, and the impact of the rape serves her character rather than her husband's.
Do Not Do This Cool Thing: The film is a horrific view of a society crippled by teenage hooligans, but it actually inspired similar crimes throughout the UK, first during its initial release (enough that Warner Brothers pulled it from theaters in England) and then after its DVD release. Some argue that if Kubrick had not made Alex so much more handsome and attractive, or dialed down some of the original evil from the novel (like the rape of two ten-year old girls converted into a consensual threesome with age-appropriate girls), this trope could have been averted entirely.
Ensemble Darkhorse: The hammy prison guard, whose uptight nature and visible outrage at both Alex and the government's method of treatment for Alex is an amusing foil to the otherwise morally ambiguous film.
Harsher in Hindsight: The reports in late 2013 / early 2014 of street thugs engaging in an activity called "The Knock-Out Game", where said thugs gang-up on a random stranger and beat the crap out the them for fun, is something straight out of Alex's alley, as shown with the scene at the beginning of the film where the droogs beat up a tramp.
Hype Backlash: This film is very divisive, despite being considered a classic, many people despise it for how it glorifies sex and violence and wants the viewer to sympathize with Alex.
Jerkass Woobie: Some people see Alex as this in the second act and the third act, considering what happens to him. A little too sympathetic a label, but his near-raped in prison, his inability to enjoy anything in life, and the merciless beatings at the hands of his victims-turned-victimizers humanize him. Of course a lot of this falls flat because some viewers note that Alex is made sympathetic because he is made weak and dehumanized.
Burgess described A Clockwork Orange as "a jeu d'esprit knocked off for money in three weeks, and it became known as the raw material for a film which accused of glorifying sex and violence. The film made it easy for readers of the book to misunderstand what it was about, and the misunderstanding will pursue me till I die."
Kubrick himself felt that the film was a sophisticated and cold satire about institutions and it was making a case for radical free will in a very artificial and stylized context, but in fact the audience latched on to Alex because he embodied and lives out in full the adolescent male fantasy of guilt-free sex and violence, and who the ending, argues becomes a Karma Houdini and even a counter-cultural rebel. Kubrick pulled out the film from theatres on hearing off copycat crimes and getting unwanted attention.
Alex did quite a few bad things, but as soon as he raped a woman in the Singing in the Rain scene, he was beyond redemption. This is partly why the twenty-first chapter is so controversial- a lot of readers think it's simply not in his character to suddenly reform.
The Minister of the Interior arguably crosses this by signing off on the Ludovico Technique in the first place. While he could be seen as well-intentioned here, he's clearly doing it for self-serving reasons, and it's pointed out that the treatment may very well be turned on anyone who resists the government. He's only concerned about crime in the first place because of overcrowding in prisons, seeing as he plans to imprison political dissidents. He's certainly crossed it by the end, when he covers up the whole incident with Alex's cooperation, essentially making a Deal with the Devil to protect himself.
The face that the old man makes when he remembers who Alex is; it's supposed to be twisted in rage and horror, but the angle of the shot and the fact that he's convulsing while bent completely forward makes it look a bit silly.
The speech given by the chaplain in the prison. Kubrick intended it to be sincere and in his interviews he said it was, but the film makes it absurd, especially because it follows the scene where a naked girl in a purple wig comes on stage in front of everyone's attendance to demonstrate that Alex's sexual urges are under control. It's not a context that serves a good speech.
Among music aficionados, the film's use of music strikes them as being really off-base. At least in terms of its associations:
The film uses overtures and excerpts from Rossini's La gazza ladra and Gugliemo Tell. The use of the climactic movement from William Tell for the fast-forward threesome scene works (since it's a very overexposed Standard Snippet associated with "the Western" genre, and the parodic part works) but using the far less well known opening overture in other parts of the film (such as when Alex wanders across London after release and thrown out of his house), and using it straight feels very weird since the music seems to be used primarily because it sounds really sombre and as such feels conventional.
For many the association of Beethoven's ninth symphony as an overarching motif feels odd. Alex sees it as a sign of culture and higher sentiments as part of his Wicked Cultured shtick, but later the film associates it with Nazi marches which seems to be mostly because Beethoven and Nazis were both German, when if they wanted to go for cultured violent kid with fascist leanings then Richard Wagner is more apropos.
Mostly, the film's classical music choices are largely those that audiences are already familiar with via Pop-Cultural Osmosis and the reliance on the over-familiarity with that music (as with "Singin' in the Rain") feels like an attempt at a Forced Meme and a fairly simple shorthand to signify that Alex is Wicked Cultured.
Older Than They Think: The first adaptation of A Clockwork Orange was in 1965, the film Vinyl by Andy Warhol. That film is some 60 minutes long, and is composed of long takes, changed the names of the characters and invented its own slang, "scum-baby" mostly, and it also used popular music ("Nowhere to Run", along with music by The Kinks and The Rolling Stones). It is however considered a masterpiece of avant-garde cinema, and it does make explicit the S&M subtext of the Burgess novel and which is also there in the Kubrick film.
Julian, Mr Alexander's nurse/protection, is played by a young weightlifter and wrestler named David Prowse. After seeing the movie, George Lucas was so impressed with his size that he offered him the part of Darth Vader.
Signature Scene: Either the opening oner, the Ludovico technique scene, or the "Singin' in the Rain" rape scene .
They Wasted a Perfectly Good Character: Mrs. Alexander (Adrienne Corri) who got raped by Alex and the Droogs apparently died of a disease off-screen (or a broken heart and trauma) if you believe her husband, Mr. Alexander. Having her Stuffed into the Fridge to serve her husband's motivation feels cheap to a modern audience, and likewise it would have made the film much more gray and ambiguous if it was her at the end receiving and welcoming Alex and deciding to either kill him or help him out of her objections to the Ludovico technique rather than her husband.
True Art Is Angsty: When the book was originally brought over to American shores, the last "Happy Ending" chapter was left out, since the publishers didn't think Americans would like it. When Kubrick began writing his screenplay, he was unaware of that chapter's existence; he read it only when he was nearly finished, and he decided to leave it out because he thought it would ruin the film's message. (The chapter was added back into the American version in 1986.)
Unintentionally Unsympathetic: Despite Kubrick's camera tricks (especially fisheye lenses) and the defenestration of Alex, it's pretty hard for a good portion of the audience to forgive Alex for his rather heinous crimes. Mostly because most of the enemies are Strawman characters deliberately made grotesque by the film's satirical focus, so it makes it pretty obvious that the film is telling us what to think and feel, and some audiences don't like that.