- Award Snub: Martin Scorsese (and many fans) felt that Jerry Lewis' performance was drastically underrated.
- Big-Lipped Alligator Moment: A minor one: as Rupert and Rita are leaving Jerry Langford's home, there's a brief shot of Rita stealing a trinket off Jerry's table. It comes out of the blue (Rita doesn't seem the petty thief type) and is never mentioned again.
- Darkness-Induced Audience Apathy: This is likely why the parts where Jerry is killed by Rupert that was suggested by Jerry Lewis himself or Rupert being beaten up by the FBI that was in the original script were omitted, given how this film for a Black Comedy is bleak as these moments. Also, the film is dark deconstruction of celebrity life and fandom with no characters to really root for, with Rita being the only 100% sympathetic character. This issue is also one of the factors behind the the film's lackluster performance at its initial release.
- Epileptic Trees: Many commentators have interpreted the finale as a dream sequence, similar to the others we see before, noting its over-the-top nature and sheer unlikeliness.
- There's also a bit of Society Marches On, at the time of the film's release, the movie's satire was seen as over-the-top because mass media still hadn't gone out of control, so seeing the ending as a dream might have made sense. Yet two decades later, the society has become so media saturated with many dubiously talented Social Climber finding fame on talk show hosts and reality TV, that the finale no longer seems over-the-top but accurate and ahead of its time.
- "Funny Aneurysm" Moment: Rupert trespassing on Jerry's property and Masha's obsession with Jerry anticipated David Letterman's trouble with Margaret Ray.
- Funny Moments: Rupert kidnapping Langford and making him read the demands off cue cards. In particular, one card being upside down, one is blank, and at one point Rupert turns them over a little too fast, and Langford despite the situation he is in, doesn't fail to remark to his associate on the phone that the statement isn't grammatically correct.
- He Really Can Act: Jerry Lewis in a rare dramatic role, it's considered not only one of his best performances, but one of the best in all of Scorsese's films. Likewise, while nobody has ever doubted DeNiro's talent, this film is often considered proof of his great range, playing a character totally unlike his previous film (Raging Bull) or any other film he appeared in.
- Hilarious in Hindsight: De Niro would later himself play a Carson-esque talk show host dealing with a dangerously deranged comedian in Joker (2019), which references this film both in universe and in story.
- Jerkass Woobie:
- Rupert tries to paint himself as one in his monologue, but it's anyone's guess how accurate it is.
- Jerry, who's not an entirely likable guy and a downplayed Nice Character, Mean Actor at best, also arguably can be considered one, a total Workaholic who lives alone with only his dog for company and is constantly harassed by crazy fans whose most harmless examples still wish him cancer when he politely turns down their request, and the worst ones are Rupert and Masha who either want to usurp him or rape him.
- Meta Twist: Rupert ironically shared some comedic quirks of characters played by Lewis early in his career (i.e. a man-child with obsessive fixation and a somewhat innocent vibe, although it's more obviously self-deceiving in Rupert's case), yet he is a Loony Fan of Lewis' character in the film, who is the complete opposite of Rupert. It gives off a vibe that the real, grounded Jerry Lewis is at battle with his over-the-top screen self and Rupert himself embodies Jerry Lewis' comedy self haunting Lewis as Langford in the real world.
- Retroactive Recognition: In the opening crowd scene, Mary Elizabeth Mastrantonio (uncredited extra in crowd scene) can be seen next to Robert de Niro just before Jerry gets into the limousine. She would later star in Scorsese's The Color of Money.
- Spiritual Adaptation: Sean T. Collins has argued that this film is the best live-action version of Joker ever. Noting that Rupert Pupkin's character, and the themes of the film anticipate many of Joker's scary-funny shtick in the last four decades. Fittingly Joker (2019) has the involvement of Scorsese and DeNiro.
- True Art Is Angsty: However, despite the Darkness-Induced Audience Apathy above, this film was still acclaimed for the dark satirical deconstruction of showbiz, fandom and fame.
- Vindicated by History: Was a flop on release, but is now regarded as one of Scorsese's best films and a classic of The '80s. When Jerry Lewis passed away in 2017, the news outlets kept bringing up this film as one of his greatest contributions to cinema (in addition his work as a comic and a film director in his own light).
YMMV / The King of Comedy