Continuity mistake: Lombard trips going up the stairs in the dark; he falls on his right side, but he waves the others to go up lying on the opposite side, facing the opposite way. (01:04:30)
Continuity mistake: During the introductions, Ilona Bergen exclaims; "How awesomely marvellous" with Blore casting on the wall by her a Hitchcockian-esque shadow with his profile. The shadow comes from nowhere, since the previous shot of the room lacked that and the other shadows (like the vase's) are unchanged. (00:06:25)
Continuity mistake: Mr. Owen is playing billiards on his own when the last survivor joins them; at the very end, it turns out that the tray with the Indian figurines is on the pool table too too, but it was not there and nobody could have added it. (01:24:50 - 01:29:10)
Continuity mistake: Spoiler; During the confrontation between the two last Indians, there is a clear position switch; her hair is in front or behind her shoulder when she says "This is how it hands." (01:23:05)
Continuity mistake: Ann is in bed with Lombard and after his reveal she asks him the name. Her hair was in front of her shoulder when she turned, and it's back behind it at the cut, and in front again at the next cut. (01:16:00)
Continuity mistake: And then there were four. They all are in the same room and Dr. Armstrong asks Ann Clyde what was she doing at the opposite end of the corridor. During the exchange, Shirley Eaton's hair is in front of her left shoulder but is or isn't in front of her right shoulder. (01:08:40)
Continuity mistake: Judge Cannon's magical handkerchief misbehaves right at the beginning of the dinner scene when he tries to make everyone else confess; it's not even in sight when he gets his tea, but pokes out a great deal when in close-up starts admitting his own guilt. (01:01:35)
Continuity mistake: During the various segments when the doctor and the judge are on their own while the others 'fix' (aka, break for good) the generator, a few times again the handkerchief in Cannon's pocket sticks out more - way more - in some shots, for instance when the doctor asks him to stop the game of cat and mouse. (00:59:40)
Continuity mistake: Upstairs when Blore messes up the generator, the Judge and the Doctor are at a standoff with their matches. The doctor has a pool cue leaning against his shoulder in the front view, away from him in the reverse shot. (01:00:40)
Continuity mistake: Blore threatens Lombard with a monkey wrench he holds with his thumb pointed up along the metal bar in close-ups, or just wrapped around it in the other angle. (01:00:05)
Continuity mistake: Blore is going in search of the generator, and the doctor approaches the light switch of the billiard room. In close-up the section of wall with the switch is nicely lit, but it is in the shadows in the camera angle encompassing the whole room. (00:58:20)
Continuity mistake: When Miss Clyde, Blore and Lombard enter Ilona Bergen's room, the Judge's handkerchief sticks just with the tip from his pocket, but sticks much more in the next of the scene before he removes it. (00:56:00)
Continuity mistake: When the doctor points at the arm of Ilona Bergen saying "Here's your bumblebee", it's in a straight line from the shoulder in close-up, but she is lying in bed with her arms pointing down. (00:56:00)
Continuity mistake: Blore accuses Miss Bergen who replies "I was on the terrace, for five minutes." Lombard piles on her misery with a comment that shows his shadow and Miss Clyde's in a completely different position and angle. (00:52:25)
Continuity mistake: Herr Grohmann decides to leave. He shuts the main door behind him, puts his hat on and walks away. His rope is on the left shoulder, and goes straight down his side. When he's shown with the camera behind him, the rope is worn across the torso. He then reaches the Devil's Leap, he's wearing the rope again along his side, and only then he puts it crossbody. (00:49:00)
Continuity mistake: Lombard and the butler are fighting. The Judge asks "Stop it! Stop it you two." In this close-up there are plenty differences in the small crowd at the door; for instance the doctor's hand is at a much higher point of the doorframe, and the actress had her hand on the judge's shoulder and now she's biting a nail. (00:45:40)
Continuity mistake: During the second dinner, the doctor asks for more wine and Grohmann pours it. The Judge's pocket square sticks out a lot, but just a tad in the close-up that follows, as he looks at the leaving Grohmann. (00:44:05)
Continuity mistake: Blore chimes in during the Judge's explanation of the mind games saying "One is bogus." Notice the shadow the Judge casts on the wall. When Blore turns towards the doctor to ask about his alibi, the judge has changed spot casting a different silhouette on the wall. (00:41:20)
Continuity mistake: Miss Bergman interrupts the game of snooker after the doctor has just taken a rather lame shot. Eyes on the ball he shot; when the Judge begins his demonstration, that ball, next to the 8 ball, it's at greater distance from it than before. (00:40:20)
Continuity mistake: When the Judge says "Mr. Owen is one of us", cue dramatic music. Miss Clyde takes her hand off the top of the chair, but she's gripping it like earlier in the next shot. (00:38:15)
