Revealing mistake: Oliver Reed heroically pummels a venomous snake made of rubber (therefore invulnerable to his heavy hits). (00:58:30)
Continuity mistake: Lombard asks the Doctor how would he know what was going through the Judge's mind, and Armstrong answers "I know because he took me into his confidence." Behind him, Blore is hunched over, with both hands together over the table. Armstrong turns his attention to Vera, and Blore now is sitting in a different pose, with his chin over his hand. (01:15:10)
Revealing mistake: When everyone enters the Judge's room and looks at him lying lifeless in bed, the room is in the dark. The light increases when the candles have been on the bedstand for a couple seconds already. (01:12:50)
Continuity mistake: When Martino is wandering the desert, delirious from the heat, his shirt is unbuttoned to half his chest or lower. When he is shown dead in a longshot, his shirt appears buttoned up higher than that. (00:51:05 - 00:52:20)
Continuity mistake: And then there were four. During their tense conversation in the lobby, the Doctor gets close to Lombard, who has his jacket in hand. He holds the jacket in a different way (sideways vs more frontal) in the two different shots. (01:15:00)
Continuity mistake: Blore is reluctant to admit his guilt. He stands up but the Judge bangs his cane angrily on the floor and Blore sits down again. The candles in front of the Judge have a different length between shots. (01:07:40)
Other mistake: Once the General has been killed during the search party, everyone is in shock and they rush to the statues, to find out that their worst nightmare is true and one more little Indian was broken. But wait; before they checked that, apparently everyone thought it was best to freshen up and go through a complete wardrobe change, because everyone is in different clothes than before. In the following scene Blore speaks with the butler in the kitchen, wearing the same tuxedo he had earlier, and not the jacket and turtleneck displayed by the Indians, and Lombard is in his room, changing into his own jacket and turtleneck that already had by the Indians. (00:42:25)
Other mistake: After the third homicide, everyone gathers around the statuettes of the ten little Indians. Small problem, though. There are eleven little Indians. (00:42:20)
Continuity mistake: After the general is killed, there's a close-up on the figurines. Two are broken with just the feet left, the third, the rightmost, at the waist. When the second victim was murdered, we saw the killer break just its head off, the statue to the right of the halved one. The following shot shows the statues in that order, with the addition of third broken one in rightmost position. (00:34:15 - 00:42:15)
Continuity mistake: During the search, when the General says "Here I am" in the wide shot, Ilona turns around, but the General in the next shot comes from a different direction, which Ilona is already facing. (00:38:25)
Character mistake: Ancient Persians had a penchant for capital punishment and elaborate tortures, but tying a woman to a column and/or strangling her from behind were not "the way the ancient Persians used to execute a murderess", despite what Lombard says. (00:33:50)
Plot hole: The killer is not designed to be a ninja with superior athletic and stealth abilities, but for Elsa's death he beats three much younger and able-bodied people who were chasing her, kills the victim unseen by her - and they don't hear her high pitched scream - and is able to get back to the hotel unseen. (00:33:25)
Revealing mistake: It's supposed to be the middle of the night when Elsa disappears, but the day for night effect is lacking to the say the least; the sun glow can be seen around the building, and the perfectly white clouds when Elsa is walking through the ruins. (00:33:00)
Continuity mistake: In the night search for Elsa, Mr. Martino spots her and starts running towards her. Not even a second passes, and in the same shot Lombard begins the chase too. In the next shot, Martino has such a head start on Lombard that Usain Bolt himself would be impressed. (00:33:15)
Character mistake: When the record plays, after Vera emphatically fists her own mouth, Hugh Lombard is called out on the murder of "Jennifer Hayes." A couple scenes later Vera is in the kitchen and asks him "What about that girl?" as they share a glass of milk. Lombard then asks back "Carol Hayes?" Spoiler; It may not be a plot hole but a mistake made by the character, since he is not the real Lombard but rather someone else posing as him. (00:18:10 - 00:32:10)
Continuity mistake: The guests are discussing how they were lured in by Mr. Owen. Aznavour pitches in with his drunken comments occasionally, but his arm/hand position is often wrong. For instance when the doctor mentions his reason, Aznavour's left arm is the only one above the music sheet, but in the close-up he's holding the glass with both hands, over the sheet. (00:20:55)
Continuity mistake: After Lombard grabbed the cassette, the Judge at the base of the stairs asks who put the tape in the machine. His cane goes from left to right hand during the quick cut to Martino. (00:19:25)
Audio problem: Since his piano rendition of the Ten Little Indians was appreciated by just 1/9 of the audience, Raven (Charles Aznavour) decides to perform one of Charles Aznavour's hits. It gets a much better reception from the audience, but it's no surprise, since everyone must be in awe of the fact that playing the song on the piano he managed to get also the accompanying sound of drums. (00:15:00)
Continuity mistake: The guests arrive by helicopter in Persepolis. They walk towards the hotel. The torrid Persian sun makes them cast a shado to their left. Elsa Martino greets them and escorts them for the last few meters in another shot, during which they cast shadows to the opposite direction. The two shots (and shadow directions) alternate. (00:02:45)
Continuity mistake: Just before he breaks the ice with the introductions, Oliver Reed is reading from a magazine, folded in two with just a page sticking out in close-ups. In the other shots he reads straight from the folded part, without stretching a page out. (00:05:05)
