Continuity mistake: Doc Riedenschneider calls on Cobby in a dark hallway with brick walls and a door in the end with a half-open transom. Through this door, in the adjacent room, there are several gangsters seated a table. They go down the hallway and enter this room. In the next scene they have entered and the seated gangsters are suddenly no longer there. Nor is there a transom over the door. The hallway viewed from this room has white walls now instead of brick.
Continuity mistake: When Joe awakens after his first night at Norma's mansion, his shirt is un-tucked as he puts on his jacket to go outside. When he is running down the stairs in the next shot, his shirt is tucked in. (00:26:35)
Continuity mistake: On the honeymoon night, when Willa approaches to the bed, Harry stands up and lights the lamp above in front of him. Between shots the lamp changes position.
Continuity mistake: In the scene where Guy enters Bruno's house to kill his father, Guy takes out a flashlight to look at Bruno's map. In one shot, you can only see the map, and the light is very small and circular, but in a wider shot of Guy's upper torso, the light covers most all of the map.
Continuity mistake: After the operation to change Vic Brady's face, the first time the bandages come off, the scar on his forehead runs diagonal from the top of his nose to well above the eye. However when he's shot by the pool, the scar runs laterally across the middle of his forehead.
Continuity mistake: Near the end, Eddie knocks down a thug who tries to stop him from putting Toro into a cab. The man's hat falls off and lands on the concrete. He gets up as the cab drives away, then turns to retrieve the hat, which has now moved itself off the sidewalk and into the bushes.
Continuity mistake: When the butler tells of Harry Lime's death, at the start of the conversation he can hardly speak English. As the conversation goes on, his English gets better and better, until at the end it's perfect with just an accent.
Continuity mistake: Pinkie sweeps all the glasses on top of the bar onto the floor, yet after he and his gang have gone we see broken glass on the bar top.
Continuity mistake: After Elsie has been kidnapped, there is a scene where a little girl walks up to an old man to ask him for the time. A man notices this and walks towards the old man. The old man is standing in front of a light pole which casts a shadow onto the pavement. In another shot, there are no shadows near the light pole.