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.
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)
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.
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)