History Film / TheExorcistIII

** Kinderman compares Ryan's lack of concern for the murder of a young black boy to ''Theatre/{{MacBeth}}'' 's lack of moral compass.

** The novel has a character named Dr. Vincent Amfortas, a depressed and suicidal neurologist. In Arthurian legend, Anfortas is the wounded Fisher King who languishes in pain (and is referred to as Amfortas in Music/RichardWagner's opera ''Parsifal''). The character doesn't appear in the film.

* PrecisionFStrike: Father Dyer told a well-connected almunus and big donor to the university, "Jesus loves you. Everyone else thinks you're an asshole."

* Retcon: This film changes the identity of the audio tech who discovered that the audio was English spoken backwards from the first film from a man to the mother of the murdered boy Thomas Kintry.

* DecoyProtagonist: Early in the film, Father Dyer seems to be a character of equal importance to Lieutenant Kinderman in the story, presented as a Deuteragonist at the very least. [[spoiler: Then, less than a half hour into the movie, he's murdered]].

* Fingore: One of the Gemini killer's signatures is severing the index finger from each of his victim's right hands.

* ShoutOutToShakespeare: Several:

** The Gemini remarks [[Theatre/Hamlet "there is a divinity that shapes our ends]].
** Kinderman compares Ryan's lack of concern for the murder of a young black boy to [[Theatre/{{MacBeth}}]'s lack of moral compass.

* ShoutOutToShakespeare: The Gemini Killer says of The Bard's plays, he loves ''Theatre/TitusAndronicus'' the best, calling it "sweet." Those familiar with the play will know why.

* AdaptedOut: The film cuts out a major sideplot involving a doctor named Vincent Amfort figuring out how to communicate with spirits from what is implied to be Purgatory (described as looking like how Kinderman sees it in his dream) as he deals with a brain tumor and morphine addiction, but that storyline didn't have a whole lot to do with the overarching narrative, hence the most likely reason it was cut altogether from the movie.

* AdaptedOut: The film cuts out a major sideplot involving a doctor named Vincent Amfortas figuring out how to communicate with spirits from what is implied to be Purgatory (described as looking like how Kinderman sees it in his dream) as he deals with a terminal illness and morphine addiction, but that storyline didn't have a whole lot to do with the overarching narrative, hence the most likely reason it was cut altogether from the movie.

** Kinderman and Dyer see ''It's a Wonderful Life'' every year.

** When asked how he is able to get in and out of jail without being seen, The Gemini Killer (Creator/BradDourif) replies: "It's child's play." The camera cuts to a young, red-headed boy who looks a lot like the [[Film/ChildsPlay Chucky doll]].

* DaylightHorror: A lot of sinister moments take place in well-lit rooms, including the [[spoiler:murder of Nurse Keating]] and the notorious CeilingCling scene.

->'''Dt. Kinderman:''' What's wrong with (the radio)?
-->'''Mrs. Clelia:''' Dead people talking.

* ResurrectedMurderer: James Venamun, aka the Gemini Killer was a multiple murderer who carved a Gemini symbol into the hands of his murder victims. Venamun's spirit became a body swapping demonic entity upon his death. Now the Gemini killer mutilates and murders people as a spirit like he did well alive.

* TerrifyingPetStoreRat: While the demon manages to conjure up a cobra in Patient X's cell during the exorcism scene, the snakes crawling all over Patient X and Father Morning are obviously king snakes and rat snakes - completely harmless and docile species often sold in pet shops.