Boom mic visible: During the police raid at the beginning of the film, a fat man hides under the bed, and is brought out by a cop. During this entire scene, the shadow of the microphone is plainly visible on the left wall of the set.
Revealing mistakes: The entire flimsy set shakes as the cop breaks through the door during the raid on Molly Murdock's place.
Crew or equipment visible: When Mae is marveling at the floor show during her first time at the club, the camera tracks around her and casts a distinct and heavy shadow across her and Molly.
Boom mic visible: The shadow of the microphone moves up the wall in the foreground when the boy with the hat is dragged into a room.