Continuity mistake: When Peach collapses on top of Mario after the weird TV invasion, Mario's arm is on top of hers, but in the closer shot that follows his arm is distant and in fact it is behind hers the moment he turns a little.
Continuity mistake: After Eugene takes the stage to face Jack Butler, everyone (including Eugene) turns when Scratch walks into the room. When Scratch sits down and Eugene turns back to face Jack Butler, Eugene's hat is gone.
Other mistake: Maureen cuts her wrists with a razor blade. Days later, no bandages or scars.
Visible crew/equipment: As Abe Vigoda pronounces the last line of the movie ("Take care, my friend"), a boom mike pokes up in full view from the bottom right of the screen.
Revealing mistake: When Eddy's mother is lying dead on the bed, she is breathing.
Continuity mistake: Jane Fonda gets out of Jeff Bridge's car in broad daylight, but when she enters the dead man's house, it's night-time.
Plot hole: Chelsea says that when her deceased father gave her one of his paintings (now missing), he wrote an inscription to her on the back. She says she cannot prove that he actually did this other than he noted it in his journal and she does not know where the journal is. However, when Chelsea's father presented the painting to her on her 8th birthday, there were at least 100 adults present at her party who witnessed him giving her the painting, writing the inscription, and signing his name on the back of the canvas which was displayed to the guests. Any number of these people could be contacted and corroborate her claim.
Factual error: Ted Bundy is trying to pick up a potential victim in front of a record store, where a poster of Stevie Nicks' album, Rock a Little, is displayed. This scene took place in the mid-1970's, but Nicks' album was released in 1985.
Factual error: The brothers had a two-way mirror installed in the fitting room. Todd makes faces at his brother through the glass. If the mirror had really been two-way, the woman would have seen the reflection of Todd making the faces and would have known something was up. (00:19:28)
Revealing mistake: During the credits, Don Falcone is reading about the bloody feud between fellow cheesemaking mafia families Lombardi and Zanetti. The first article he browses is the April 7, 1985 edition of the Italian newspaper "Il Messaggero," with a bad glue-on job (the left column's font does not match the rest of the actual newspaper). He then reads about the car bombs in another newspaper, "Paese Sera." Here the prop design is better, but if you can read Italian, you can easily see that the article does not match its headline at all; it's not about a brutal mafia murder, but rather about the "sliding wage scale" referendum which was taking place in the country at the time the movie was shot, in 1985. (00:03:00 - 00:04:15)
Other mistake: The end credits are plagued by the biggest compilation of spelling mistakes you'll ever see. The French cast in particular has 2 out of 2 actors with their names wrong (PallarOy instead of PallarDy, a female, Danièle, turned into a male Daniel) and so many errors in the technical cast to make some of them impossible to identify.
Continuity mistake: The amount of roaches in the bowl at the bar changes from less to more.
Continuity mistake: Marjorie sprays the rapist in the left eye, mostly, with insect spray, but later it is his right eye that is affected the most.
Revealing mistake: When the bully's held up by Sam wires can be faintly seen.
Continuity mistake: Poirot met Ariadne Oliver who invites him to the "murder hunt." Poirot and Hastings then get on a boat to head there. As they sit on the boat, there are a few extras, led by an easily identifiable lady in a yellow sweater, that move up the stairs of the pier and reach the top. The boat slowly takes off, and about 10 seconds later we see the pier again, with again those same people from before just reaching the top of the stairs. (00:02:25)
Visible crew/equipment: When Crispin Glover goes into a telephone booth to make a call, the cameraman and his camera are reflected in the glass.
Continuity mistake: To reach Poirot, Hastings walks through the Acapulco airport with two ladies (one with a white jacket, light blue skirt, updo, carries a large brown suitcase, and another one with short hair, glasses, white trousers) that are both in front of him AND behind him, depending on the camera angle. (00:01:30)
Continuity mistake: Martin McNamara calls his brother at the beginning of the movie and tells him he'll be ready in two minutes. When the camera cuts to a new shot, his grip on the phone changed entirely.