* AdaptationDisplacement: The 1944 film is better known than the play and the UK film version it's based on. The studio tried to enforce this by having all prints of the previous version destroyed (so, ironically, they were trying to gaslight people out of remembering that the UK version existed). Ironically the remake had the title 'The Murder in Thornton Square' for the UK release to avoid confusion - but of course the original title is used these days.
** Meta-example. These days, the term "gaslighting" itself, and what it means, is more well-known than the movie that named it.
* CatharsisFactor: The ending, when Paula furiously throws Gregory's abusive gaslighting techniques back in his face before calling in Brian to take him away.
* CommonKnowledge: This is one of the great moments of Creator/AlfredHitchcock's career... except, it was directed by Creator/GeorgeCukor. It's easy to see why people would think it's a Hitchcock film, though: it's a classic PsychologicalThriller, with a OneWordTitle, and frequent Hitchcock leads Creator/IngridBergman and Creator/JosephCotten are in it. He did direct a similar film called ''{{Film/Suspicion}}'', which has the opposite climax [[spoiler: where the man turns out ''not'' to be a murderer]].
* EnsembleDarkhorse: Creator/AngelaLansbury as Nancy, the Cockney maid, made enough of an impression to get an Oscar nomination, even though she's, at best, the sixth-most important character in the story. The impressive thing is that she had no acting training, and was just a natural in front of the camera.
* HilariousInHindsight:
** Angela Lansbury playing an oblivious pawn ([[spoiler:and RedHerring]]) in a murder mystery first becomes amusing as of ''Literature/DeathOnTheNile'' - where she's a crime novelist who unsuccessfully attempts to solve a murder mystery. And then of course with her famous series ''Series/MurderSheWrote'', which is about her solving mysteries. Plus, she [[Film/MaryPoppinsReturns sings about balloons]].
** Joseph Cotton played a killer himself in ''Film/ShadowOfADoubt'', and he'd be on the other side of a [[spoiler: {{Gaslighting}} plot]] in ''Film/HushHushSweetCharlotte''.
* ItWasHisSled: An odd case where the original play and its earlier film adaptation are clear from the start that the husband is a jerk who's deliberately manipulating his wife, but the more famous film tries to make it a twist with Gregory able to put on a believable front as a loving, sympathetic husband. Of course, the fact that the very title has become an official term for this kind of abuse gives things away these days.
* MemeticMutation: The term "gaslighting" has become a byword for MindRape tactics used by domestic abusers. Ironically, [[spoiler:tampering with the lights was the only aspect of Gregory's abuse he did unintentionally.]]
* ParanoiaFuel: It's written into the film! Gregory has Paula doubting her own sanity so easily, which can be very alarming at how effectively he accomplishes it.
* RetroactiveRecognition: A 17 year old Angela Lansbury makes her film debut as Paula's maid.
* SignatureScene: Paula confronting Gregory and giving him TheReasonYouSuckSpeech - while {{Troll}}ing him with her apparent madness. It's considered one of the finest moments of Ingrid Bergman's career.
* TheUntwist: Gregory being [[spoiler:the letter's sender or his accomplice]] and [[spoiler:Alice Alquist's murderer]] becomes painfully obvious once the letter is brought up, thanks to his bizarre and violent reaction to Laura finding it.
* ValuesResonance: The film examines psychological abuse that can happen in marriages and relationships, and Paula comes out the other end able to confront her abuser and not let what he did to her rule her life.
* TheWoobie: As Paula's constant undermining by Gregory takes its toll, it's hard not to want to give her a reassuring hug.
--> '''Paula:''' You mean we're not going to the theatre?