Continuity: When Martha Phelps comes to see Flywheel, he's pretending to talk on the telephone. When he hangs up, he puts the receiver upside-down in the cradle, but in the next shot it's in the normal position.
Revealing mistakes: The bike which Flywheel rides around the store starts out as an ordinary chain-drive bike, then abruptly changes to a strange contraption with the pedal cranks attached directly to the rear axle (which permits the bike to fall apart when Flywheel runs into a pillar, leaving him riding a unicycle).
Revealing mistakes: When Wacky is propelled up through the open elevator roof door, the wires pulling him and the outline of his back harness are clearly visible.
Revealing mistakes: When the brothers are barricading themselves in the electrical supply room, as the light bulbs are falling (and sounding like gunshots), the close-up clearly shows a white string pulling the rear of the shelf up and some of the mechanism lever is visibly moving at the top-right of the shelf.
Revealing mistakes: Obvious doubles for the Marx Brothers during the finale chase sequence (except for close-ups).
Continuity: In Mr. Grover's office, Mr. Grover closes the account book and keeps his hands on the sides of the book, but in the next shot he has his hands crossed on the book.
Continuity: After he delivers the record to his fan, Tommy sits down to talk with Joan and crosses his hands on his legs. Next shot he is holding a pencil.
Continuity: When Wolf, Ravelli and Wacky meet Tommy, Wacky has his right arm by his side. In the subsequent shot, when he shakes hands with Tommy, he has his right hand in his pocket.
Continuity: In the scene at Flywheel's detective agency, a wall calendar can be seen displaying a large "8". In subsequent shots the calendar reads "11".
Revealing mistakes: During the chase scene, when Wacky roller skates into the elevator, a store directory posted on the wall is backwards, indicating that the shot has been flipped.