It's hard to think of a movie more divisive — both at the time it was filmed and today — than Stanley Kubrick's adaptation of Anthony Burgess' dystopian social satire A Clockwork Orange. The novel was already controversial enough (the film, as brutal as it seemed upon its release in 1971, actually toned down much of the book's violence, and substituted a consensual sex scene for Alex's rape, in the novel, of two preadolescent girls), and while the film did what it could to make a savage treatment of youth violence palatable to censors, it still earned an X rating in the United States and raised such objections in the UK that Kubrick voluntarily withdrew it from release, and stipulated that it not be shown there again until after his death.
Even beyond that, both book and movie are plagued with inconsistencies, misinterpretations, and resentment: the novel was released in the United States without its critical final chapter (it was finally restored in 1986), which entirely changes the reader's perceptions of what had gone before. Kubrick himself had only a minimal interest in remaining faithful to his source material (which had been given to him as a gift by his friend and favorite writer, Terry Southern), while Burgess — paid only a pittance for the film rights — had his own misgivings about a movie version of his then-notorious book. "I feared that the cutting to the narrative bone which harmed the filmed Lolita," he said, "would turn the filmed A Clockwork Orange into a complementary pornograph — the seduction of a minor for the one, for the other brutal mayhem.
The writer's aim in both books had been to put language, not sex or violence, into the foreground; a film, on the other hand, was not made out of words." A Clockwork Orange was, indeed, made not out of words, but out of images, and it was those images — often of vicious sociopathic behavior to which the viewer is made an uncomfortable witness and even accomplice — that defines the movie just as the elegant (and deliberately deceptive) use of language defines the book.
WHAT IT HAD: A truly visionary director — one of the greatest of all time — who could not have been more perfectly suited to bring to the screen the bleak, cold, stylized dystopian London of Burgess' novel. A script that, while it may have lacked the writerly approach to language and truth that permeated Burgess' source material, at least remained surprisingly faithful to its story and made a largely successful attempt to bring the 'Nadsat' slang used by the droogs in the novel to the big screen. A hypnotically compelling lead performance by a young and terrifyingly believable Malcolm McDowell. A brilliant soundtrack by Wendy Carlos that matched the mood and tone of the film to an uncanny degree. A handful of some of the most memorable scenes ever put to celluloid in a science fiction film. 
WHAT IT LACKED: A man at the helm who possessed the same deep and abiding sense of linguistic play as the author of the book. A director whose ability to write a script was as sure-handed as his ability to frame a shot. A strong secondary cast. A sense of political commitment and philosophical heft as deep as its source material. An ability to easily distinguish between violence presented to shock and violence presented to titillate, and a willingness to make the viewer care about the difference. A true satirist's moral center, and a true storyteller's ability to put ambiguity in service of the truth. A reluctance to go out on a sour note that felt exploitative. The final chapter, which did so much to make sense of the book, but which, when left out, leaves behind a somewhat incoherent film.
DID IT SUCCEED?: It succeeded hugely on its own terms, but what terms were those? Kubrick's specialty was subtlety of emotion, not subtlety of intent; he was a visual filmmaker, not a philosophical one, and a story as deeply philosophical as A Clockwork Orange was done something of a disservice by being placed in his hands, no matter how stunning the film is to look at and how long its best-known setpieces stay with you. Kubrick's determination to provoke provides them movie with some of its finest moments and some of its worst; and while the movie is not without its ambiguity, it sacrifices profundity for power, which is not always an acceptable tradeoff. However, it does what it sets out to do so spectacularly that it's almost churlish to note that Burgess' fears about the filmed version of his novel came very precisely true.