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)
Continuity mistake: Ilona tells the judge that the chansonnier is nearly done with the cacophony; in longshot her arm is stretched forward, but she has her hand (and glass) close to her face in close-up. (00:13:20)
Continuity mistake: At the end of the Ten Little Indians song, Lombard from his spot at the base of the staircase produces arguably the most awkward thumbs up and grin in cinematic history. He then moves to a chair next to Vera, reading a book. But during the performace of the Aznavour hit "The old fashioned way" that follows, he gives Raven another, marginally less awkward, thumbs up. By the background you can easily tell he's again standing by the stairs, in what was most likely another take of the gesture from before. (00:14:00 - 00:15:45)
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: At the end of "The old fashioned way", Aznavour thanks the audience and lifts his glass for a drink right as Owen's voice comes through the speakers. Wide shot, and you can see him only then, after a couple of seconds actually, lift the glass. (00:16:40)
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: 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)
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)
Plot hole: In this version more than any other there's an implausibility about the first murder. Here it is stated that the poison is in the bottle and not the glass (which would have made other versions such as the 1945 one more plausible), but we can actually see Charles Aznavour drink from the glass (when he stands from the piano and leans his back against it) way before his death, and not pour himself any new liquor afterwards. (00:22:50)
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)
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)
Other mistake: The murderer is not a ghost or someone with supernatural powers, but he strangles Elsa from a spot she stepped on before the cut, and with no other possible item or structure they could have been hidden by. (00:33:25)
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)
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)
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)
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)
Continuity mistake: Vera screams "No!" as Martino tries to pour her a drink. The man is holding the bottle with both hands in the next shot, in discontinuity with the pose he had before, leaning with the other hand against the back of the chair. (00:47:30)
