When Jeff first gets on the train, his badge keeps changing position on his coat.
Multiple different-sized actors, in noticeably different gorilla costumes, were used to play Gibraltar the gorilla.
In the long short, Peerless Pauline is shown putting the wallet into her costume on the right side with her left hand. In the close-up, the opposite is shown.
Peerless Pauline leaves Loophole hanging from the ceiling. Punchy stands on a trunk and unties the suction-cup shoes on Loophole's feet. Once the shoes are untied, the stunt double playing Loophole pulls his feet out of the shoes and bends his knees before "falling."
During the "Swingali" number, three boys playing saxophones stand up and play "Auld Lang Syne," but the instruments heard on the soundtrack are clarinets.
When the little boy is "playing" his trumpet solo (and Punchy is using the bulb of his bicycle horn as a wah-wah mute), not only are the boy's fingerings incorrect, they are out of synch with the sequence of notes. Punchy's use of the "mute" is likewise out of synch.
Mrs. Dukesbury introduces Jardinet's first piece as a Ludwig van Beethoven piece. It is in fact Richard Wagner's 3rd Act prelude from Lohengrin.