Other mistake: The flashback that shows when the culprit is able to inform the accomplice that Mrs. Ottenbourne is about to expose them differs in many small details from the original; when she enters the room, Ustinov by the door fixes his jacket with one hand, and in the original scene he did it with two, when Simon urges her to tell the story from the beginning she has her hand on her chest in the flashback and not in the original. And her last words are "I saw that it was" vs "I saw it." This is no subjective, hypothetical flashback. (01:48:05 - 02:10:05)
Other mistake: When Poirot questions Maggie Smith, he repeats what she said about Linnet Ridgeway "three days ago." Besides the discrepancy in dates (it was the day before the murder), Poirot at the time was dozing off on the portside deck (mrs. Ottenbourne passes him by going across) so he could have eavesdropped on the conversation in the near area, but not on that particular one which happened on the starboard deck.
Other mistake: Poirot has uncanny hearing abilities, since he could pick up word for word the conversation Miss Ottenbourne and Ferguson were having several feet behind him at the temple of Karnak. He has also perfect memory, and yet he says that the girl asked the question about libeling the dead "two days ago." The murder (in the movie at least) happens the same evening of the visit at the temple. (01:14:50)
Other mistake: During the denouement, there is a scene with the meeting between Simon and Jacqueline inside the doctor's cabin. Jackie opens the doctor's case where he keeps the surgical tools pulling it out from a drawer, and she does not place the box back in the drawer or closes it; we see the whole time she spends inside the cabin, so it'd be impossible for the doctor not to notice what happened. (02:08:25)
