Revealing mistake: When Dr. King checks on Mrs. Boynton, the dead woman opens her eyes by her own volition before her head rolls back. (00:45:00)
Revealing mistake: In the close-up of the killer's revolver firing, the revolver is...clearly not firing. It's just the sound dubbed in, but there's no flash or discharge of any kind. (01:33:10)
Revealing mistake: When Poirot reads the newspaper detailing Lady Westholme's death, the font and the clarity of the print on the article stick out from the rest of the page like a sore thumb. (01:38:30)
