Continuity mistake: During the sentence when Hastings tells Poirot he's got "No imagination at all", the lady sitting behind the Belgian faces the other way between shots. (00:02:25)
Continuity mistake: Poirot shows Hastings Nicki's hat; he holds it in a different way (using the thumb to pinch, or with the light brim tucked in between index and middle) between shots. (00:08:55)
Continuity mistake: Poirot and Hastings are eating after their first visit to End House. During the entire scene, natural light changes in intensity depending on the angle of filming. (00:20:15 - 00:21:10)
Continuity mistake: When Poirot shows Freddie the bullet, in the close-up his hand is right by the sugar bowl, but he was shown putting the cigarette holder at greater distance, closer to Freddie herself. (00:25:05)
Continuity mistake: When Mr. Vyse is beginning to talk about the new will, in the wide shot encompassing the whole table, the open folder is raised, as the left page is sitting on top of another object. In the close-up of the letter, the folder is perfectly level with the table. (00:34:45)
Continuity mistake: Once Ghost Nick enters the room and Poirot turns on the lights, the Crofts stare at her, and you can see in frame the right arm of "Mne LeMon", sitting by Milly. Next shot though, Miss Lemon is standing on her feet. (00:40:10)
Continuity mistake: Poirot rudely awakens Hastings with his three questions. You get a good view of Hastings' wristwatch on the bedstand. When at the end of the Q&A Hastings turns his attention to the watch, it is in a completely different position. (00:41:25 - 00:42:35)
Continuity mistake: When Freddie holds the Mauser 1910 gun, Alison Sterling holds it in a very characteristic way (thumb and and pinky finger stick out) in the front views. It is held in a much more orthodox way in the views from behind. (00:43:50)
Continuity mistake: Poirot and Hastings are talking with Freddie, by her invitation. She says "You'll be giving me a diploma next" and three extras walk by her chair. In the following shot she completes the action of standing up, but the extras are still there, behind their original positions. (00:44:15)
Continuity mistake: Jim Lazarus pulls over by the protagonists to complain about being unable to see Nick. During the scene, Paul Geoffrey's different facial expressions are shown in the side mirror of the car, but each time we cut back to him, he has the same stoic face listening to Poirot. (00:47:00)
Continuity mistake: Miss Lemon's ice cream quite literally melts between shots (and the actress ignores the dripping on her fingers). (00:51:15)
Continuity mistake: Poirot meets Hastings about to go play golf with a Stiffie. Hastings holds his hat by the brim, which turns into the crown in the reverse shot. (01:02:05)
Continuity mistake: Commander Challenger in front of his boat laughs with Hastings "I hope my alibi is in order." As he says that, Hastings nods. During this close-up, his hat is casting a completely different shadow, covering his whole shoulder instead of just the back of the neck as in the rest of the scene. (01:03:35)
Continuity mistake: When Japp talks to Poirot and Hastings about the gallery troubles, the peppermint rock candy he is waving is wrapped differently between shots. (01:13:40)
Continuity mistake: Starting the seance, Poirot ask everyone to hold their hands. Lazarus barely stifles a laughter. Between that shot and the previous, his hand goes from above the table to underneath it. (01:38:25)
Continuity mistake: At the beginning of the opening credits, there is a close-up of the model boat pushed forward. It passes by a kid who is hunched over, hands on his thighs. Wider shot, and the kid just watches the sailboat pass by standing apathetically. (00:02:15)
Continuity mistake: Sitting on the park bench, Japp narrates the jewelry heist to Poirot. The passersby during the scene change in the various angles, and the most evident demonstration is offered by the fella that starts his walk exactly when Japp sits down. Grey pants, a sleeveless vest and hat, he walks all the way to the path in the background and exits stage right. But he's walking behind Japp when he says "The stones in his pocket were not the real stones." (00:03:00 - 00:03:45)
Continuity mistake: When Poirot and Hastings enter the Athena, there's an establishing shot as they walk to the right of the concierge. In the following shot, some elements like the lady with the flower dress by them are consistent, but the desk employee is suddenly on the phone and a bellboy appears by the stairs. Also the lady in the corner changes from a blonde to an elderly woman in a red coat. (00:05:50)
Continuity mistake: Poirot tells Miss Lemon to calm down because "It is only the simple blackmailer." Pauline Moran has her right hand on the bag, but in the close-up that follows her hand is at a distance from it. The difference in position (and thus in the takes being edited together) is reflected by a mistake happening a few seconds later, when you can notice as she turns around to answer the door, that her gloves have also switched hand. (00:12:10)
Continuity mistake: Lavington puts his hat on the couch before talking to Poirot. The hat shifts closer to Hastings and then back closer to the armrest during the scene. (00:12:45 - 00:14:30)
