Character mistake: Blore accuses Lombard saying "What about those 21 poor natives in South Africa?" The record played during the first evening mentioned indeed 21 men, but that were natives of a tribe in East Africa. (00:14:20 - 01:10:10)
Character mistake: The killer in the original novel (and as reminded also in this adaptation) stages his homicides following the nursery rhyme; goes through great lengths to do that, including planting a bumblebee in the room, using a hatchet, etc. But Blore's death has nothing to do with a bear, since he gets crushed by bricks. Conveniently the rhyme is not mentiones by the characters at all for his death, while they were the first ones to recite the matching verse in all the other deaths. In the original novel, Blore gets killed by a heavy object shaped like a bear.