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)
Revealing mistake: When Cabal and Passworthy look upon the distant searchlights from their doorstep, it's plain that the "beams" of light are really just solid dowel rods being swung about.
Continuity mistake: After the bad guys frame Cagney for drunk driving and stage an auto accident, the smudges on his face change shape and position several times between shots. (00:27:30)
Factual error: John Blair rides for the pony express, which operated until October, 1861. However, all of the handguns in the movie are cartridge Colts, which did not come into existence until 1871.
Continuity mistake: In the scene where Buffalo Bill is about to be ambushed by Indians, he has a light coloured hat. In the close up shot of him he has a black hat.
Continuity mistake: When Porky Pig falls asleep in his boat, he is wearing a red shirt. In his dream, a big fish cuts off the red shirt to cook a now naked Porky. When the dream ends and Porky wakes up back on his boat, his red shirt is still missing, and he's still naked. He should have still had his red shirt on.
Continuity mistake: When we first see the Owls' house at the start of the cartoon, the violin sign above the door entrance reads "Prof. Owl." But in a close-up of the sign in the next shot, it now reads "Prof. Fritz Owl."
Factual error: This movie takes place post-civil war, and Fisher, in his first discussion with General Cortinas refers to the "Republic of Texas" being ripe for the taking. Texas ceased to be a republic in 1845, when it joined the United States.
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.
Continuity mistake: Todd meets Mr. Beadle outside of his shop with a new apprentice for him. Beadle strokes his chin as he mentions the 7 guineas, but his hand is firmly on the boy's shoulder at the cut. (00:07:55)
Continuity mistake: At the end of the establishing continuous shot in the lobby, Bert leans against the desk and whines; "This is the kind of night that gives me the willies." The clerk rolls her eyes; she is holding a note between the two hands and you can see right before the cut that the note stays in her left as she lets go with the right. The new shoot though begins with the note in her right hand. (00:02:45)