Revealing mistake: In the first scene on Ginger's sister's boat that's being refitted, one of the seagulls (yes they used real seagulls) flies over the stern end right into the cyclorama and takes a nose dive to the stage floor.
Continuity mistake: During the visit of the Minister in jail, Charlie sits next to the Minister's wife. The distance between them varies between shots. (00:30:40)
Continuity mistake: When mother says "I think you were a bit too hasty" to father, the door is completely different to the one seen when father threw out his son only a few seconds ago.
Factual error: Charlie Chan claims that mixing hydrochloric acid with ferrocyanide of potassium is mixing two acids. Ferrocyanide of potassium is not an acid. (00:27:00)
Continuity mistake: The lawyer and his two collaborators arrive in Mandrake Falls and reach Longfellow Deeds' home. The housekeeper opens the door to let them in...and never bothers to close it (and it does not close by itself). Few seconds later, Deeds' arrival is announced by the dog who impatiently paws at the closed door. (00:04:50)
Continuity mistake: When we see "Ben Birdie" on the stage at the start of the cartoon, he is surrounded by a piano, tuba and a drum, but when a mouse appears out of the tuba in the next shot, the drum has completely disappeared.