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)
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)
Other mistake: Throughout the 'blackout', no lights at all work and everyone has to get by with candles, torches and their own flashlights, but the main hall is perfectly lit, and even when they go rescue Vera who cried because her candles were blown out, the corridor behind Lombard has enough light to allow anyone to see without any problem. (01:11:10)
Other mistake: Despite Blore having shorted out of the generator the night before, when the last survivor gets back to the hotel for the finale, all the lights in the lobby are back to normal. The killer is smart, but not an electrician. (01:30:25)
Other mistake: The end credits list the cast, so it says, "in order of their disappearance." But it's not true; Ilona is listed before Martino, who disappeared earlier than she did (52:30 vs 58:20), Blore is listed before Armstrong, who's been dead longer, and Lombard is the very last, while he was the Indian number two.
