Continuity mistake: When Vera reports the General's ominous phrase "He said the boat will never come", she's standing by the window - the leftmost window of the dining room, as visible later - but she wasn't there a moment before, when Quincannon and Armstrong were talking. (00:33:30)
Continuity mistake: Lombard on the cliff says "Mr Owen's hand is plain to see"; at the cut, the clouds in background are different, and the hat on Barry Fitzgerald's head adjusted itself - it was about to fly off in the previous shot. (00:32:10)
Continuity mistake: The men are looking down the cliff in search for possible hiding places. Blore asks the doctor if he OD'd the maid; he does it without a hand on his hat (he lowered earlier in the first shot) and then with the hand on it in the next shot. (00:31:50)
Continuity mistake: Vera approaches the General on the beach. He calls her "Juliet", mistaking her for his dead wife; during the close-up on June Duprez, the lighting is different and the foulard is windblown harder. (00:31:00)
Continuity mistake: Miss Emily Brent points her binoculars at the beach in the same shot when the men decide to start searching the island. She witnesses a brief exchange between Vera and the General, then follows Vera's movements who are in strict continuity. Merely a minute has passed, and the guys already are on the beach (which already can be quite a feat) discussing how their search was fruitless. They haven't searched a thing in so little time. (00:30:25)
Continuity mistake: Vera reaches on the beach Gen. Sir John Mandrake. When she exclaims "Sir John!" after he asked her (or rather, his dead wife) why does she love 'him', the sky is overcast and the shadows change radically in the next shot. (00:30:50)
Continuity mistake: In the scene with the various characters (Blore, the doctor, the judge) spying on each other, the keyholes the camera looks through are always perfectly lit, with none of the shadows the characters cast on the lock in the other views. (00:27:25)
Continuity mistake: Blore asks Lombard from the other side of the door "You mean you haven't any weapon?", hands off the handle. Hand on the handle in the shot that follows. (00:27:30)
Other mistake: When the judge and everyone else observe and comment the fact that two figurines are broken, nobody has a clean line of sight to them; they talk about what the movie spectator is seeing. (00:24:30)
Continuity mistake: When the doctor announces that "Mrs. Rogers died in her sleep", the Judge 's hand with the pipe goes from in front of the chest to down his side. (00:25:00)
Continuity mistake: After his confession, the prince plays the piano no-stop when he's not in frame, but the glass awaits him closer on the sheets than it originally was when he picks it up to toast yet again. (00:19:30)
Continuity mistake: The prince tells the sad story of his driving license revoked - with two people dying as collateral damage. Judge Francis J. Quincannon stands and then leans over the back of the chair; his arms switch position, crossing with the right in front, then the left in front. (00:19:50)
Continuity mistake: When Mrs. Rogers yells at her husband, behind her in close-up you can see on the portion of floor in frame the silverware she was carrying and that is by her; she moved forward quite a bit. (00:16:20)
Continuity mistake: At the end of the macabre performance at the piano by Mischa Auer, he grabs his drink and raises the glass - which is lowered at the instantaneous cut to a new angle. (00:13:30)
Other mistake: When we see Rogers remove the record from the sleeve, the grandfather clock behind him shows it's 9 o'clock. Several minutes follow as the recorded voice lists all the crimes of the 10 Indians, and in particular when Mrs. Rogers faints, behind her you can see the clock is still stuck at 9 o'clock. The clock returns to advance, and does it quickly, after Rogers hands the note to the judge and Mrs. Rogers yells at him. (00:12:50 - 00:16:10)
Continuity mistake: Blore gets up from his chair during the Ten Little Indians song. Through the doorway you can see the Doctor and the Judge playing pool; cuts to a closer view and Dr. Edward G. Armstrong is in an entirely different posture and position. (00:12:35)
Continuity mistake: While Prince Nikita Starloff plays at the piano in a creepy deep voice the Indians song, a poker game is going on. Rogers serves the drinks; at the cut when he walks away, the General's pipe switched side of the mouth. (00:12:15)
Continuity mistake: As Ms. Claythorn recites the first verse of the nursery rhyme, Lombard picks up food from the platter. He gets two pieces, then puts the utensils back; notice in the following shot how his arm is suddenly in a different and rather awkward position, the waiter being at closer distance. (00:11:15)
Continuity mistake: When a drunk Prince Nikita Starloff is quick to make yet another toast in honor of the Indians and their statuettes ("I drink to the Indians!"), Lombard who had his hand down on the table, has it raised in front of his chest. (00:10:55)
Continuity mistake: After the toast to Mr. Owen, the General retorts that hopefully all the possible toasts are done. Vera Claythorne puts down her glass, but in the next shot the whole arm is gone from above the table, she has her hands in her lap. (00:10:35)
