Continuity mistake: When the two men talk in the tent at the beginning, watch when one turns around - there is a clear cut in mid action where the men's positions change without any movement. (00:13:05)
Continuity mistake: When Chico and Harpo bring Groucho ice in his office at Huxley College, Harpo is wearing some kind of earmuffs. Between shots they change from going round his chin to behind his head.
Visible crew/equipment: When Dr Moreau is showing Parker his plant experiments there is a moment, just after Moreau says "That's one there", when the camera moves past a pillar and the shadow of some equipment is cast on the pillar. (00:30:28)
Continuity mistake: When the Baron is dead and Mr. Kringelein enters in the room, he kneels by him and says a few lines about him looking peaceful. His left arm is on the chair in a position different from the shot before and after, where the hand is at the end of the armrest.
Audio problem: During Joe and Eddie's first race, you can hear the sound of squealing tires as they round the bend. But they're driving on a dirt track. Tires don't squeal on dirt. (00:15:40)
Continuity mistake: The natives approach the ship; one in particular is shown swimming putting her feet right against the bow. One of the crew members pours their drink in the ocean; there's a sailor that walks behind him and makes a sharp left turn. Next shot, and the man is gone, but reappears a second later from the original starting point repeating the walk and turn. (00:05:30)
Visible crew/equipment: When Stan and Oliver walk up the steps to their flat after "borrowing" money from the bank, the shadow of a boom mike is following them up the steps.
Continuity mistake: When Oliver introduces Stan to Harry at the snack bar, you can see that Harry's right arm is by his side but in the next shot it is resting on the counter.
Plot hole: When Oliver attempts to lift the drain grille in order to get the drunk's car key, he claims it is too heavy. Yet when Stan gets his umbrella stuck down there, Oliver manages to lift the grille without any effort.
Suggested correction: Ollie doesn't say too heavy, he just says "this thing is heavy."
Revealing mistake: Ollie throws a flower pot at Stan. Stan ducks and the pot continues through the house, breaking a window and hitting a gardener outside. On the DVD of the film, the long wire the flower pot is attached to is visible.
Continuity mistake: When Oliver falls into the fountain with the wooden crate, you can tell the crate is empty because it is floating. But when we see a close-up of Oliver in the next shot, the crate has been weighed down and is not floating.
Continuity mistake: When we see Oliver reading his newspaper at the beginning of the short, the door behind him is open. In the next shot, the door is closed, and in the following shot, the door is open again.
Continuity mistake: When Harold climbs in the window of his house, his car rolls away to the right. After hearing the crash, he runs back to the window and looks out - to the right, where he sees the wreck. But that's the wrong direction. From inside the house, the wreck should be to the left. (00:08:00)