Revealing mistake: When the kids step out of the water and walk towards the house, the floor is already soaking wet from previous takes.
Continuity mistake: When the Leslie Special is rolled out to be presented to the Great Leslie the red carpet in the front view starts at the building alignment. The aerial shot as seen from Professor Fate shows a wide gap between the building alignment and the red carpet.
Continuity mistake: In the scene where the Beatles are in bed sleeping, and Ringo is getting pulled out of bed by the ring, he falls out of bed, and brings the blankets with him. In the next shot however, the bed clothes are back on his bed.
Continuity mistake: In the scene where Rusty is trying to keep Dana and Valerie from seeing each other, it is supposed to be night time. But, when Rusty opens to curtains to usher Valerie out the door, you can see that the sky is much too light to be night time.
Continuity mistake: During the second solitary visit that the Native Girl pays to doctor Bwana, she has to hold him steady after he drank the torpedo juice. Her right hand is in a completely different position in the various shots, and she lets Buster Keaton go once but is still holding him after the cut.