When Larry and Curly rush to Moe after he falls through the ceiling, his work coveralls are spotless. This is due to a continuity error in the stock footage from Pardon My Scotch (1935), when Moe had paint all over his coveralls after crashing back down to the first floor.
The mannequin head that Curly holds disappears after cutting back to the gorilla.
The middle of the three walnuts on the table isn't broken, but in the next shot, it is.
Curly is suddenly looking at the commissioner, even though he was looking at Dill in the previous shot.
Mr. Dill calls the inspector "commissioner" even though his desk plate says "police inspector".
After Curly spins on the floor, Larry can be seen laughing when he is trying to help him up.
When Moe bumps Larry and Curly's heads together, there is an awkward pause, after Moe says, "Why, you rat!"
When Curly notices Larry getting beat up by a henchman, what appears to be a flatulence sound can be heard.
When Moe pushes Curly back through the door, the latter's hat falls off and Moe ad-libs "Get that hat!"
The paint from the phone that the chief gets hit in the face with leaves marks on it.
When Curly gets stuck in the guillotine, he says, "I cut my head off. I'm dead." However, it's clear he's saying something else.
The wire is visible that makes the cat's tail move back and forth.
Before Curly headbutts the gorilla, he says "I've had enough of him, too!", but he did not say that about anyone else.