Continuity mistake: Near the end, as a plane is getting ready to run down the airstrip, Bogie knocks the gunman out, then uses the gun to shoot the plane in its tracks. When the machine gun starts to fire, it has a long strip of bullets, then fewer, and so on.
Continuity mistake: When Reginald Owen who is a British agent posing as a German hits a German Captain on the head the German doesn't have a hat on.When he pushes the German out of the car when the body falls out it has a hat on. (01:31:45)
Continuity mistake: When we see Elmer reading his book at the beginning of the cartoon, the strap of his gun switches shoulders between shots.
Continuity mistake: Robert Cummings is talking to a Viennese doctor. The doctor lights a match for his pipe. Then, in the next shot, there is no match.
Continuity mistake: Bela Lugosi offers John Berkes a cigar ("a real Havana"), but when he's relaxing, he calls him by his 'street' name, Fingers. The man nervously brings a hand to his collar, but at the cut Fingers' fingers are gone out of frame. (00:06:30)
Continuity mistake: When Daffy sees Dr Jerkyl's house, he is holding a telegram in his hand that disappears when we see him in the next shot.
Factual error: Those in America, mainly in Massachusetts, weren't burned at the stake when accused of witchcraft. They were hanged. It was those in Europe who were burned at the stake.
Audio problem: When we see the moth singing on his way to the bar, his mouth doesn't move.
Continuity mistake: When Jerry runs onto the record player, he runs next to a button panel and there are four buttons on it: Fast, Stop, Start and Change. But when he is pressing random buttons later on in the cartoon, a "Record" button has been added and the "Change" button has disappeared.
Factual error: The events depicted in the movie occur around the time of the California gold rush in 1848, yet every man and his dog wields an 1873 Colt Peacemaker.
Continuity mistake: When one of the doctors puts an alarm clock next to Donald's head, the time on the clock initially reads 2:00 but in the next shot changes to 4:00.
Continuity mistake: When Elmer is digging a hole to put a stick of dynamite in to try and find gold, the circle of the hole has earth around it. When he runs for cover after putting the dynamite in the hole, the earth is completely scattered, and when he puts the dynamite back in the hole before zipping it up, the earth is back around the circle.
Continuity mistake: When Ala Bahma is performing the pulling the rabbit trick at the theatre, the curtain behind him is blue. But when Bugs appears and offers to help him, the curtain is red.
Continuity mistake: When Holmes reveals that Sir Evan is the mole, the Nazi gives a big smile and we can see that his entire right cheek is shadowed. In the next shot, there is no shadow on his face and he remains serious. In the next shot, Sir Evan smiles again and the shadow has returned. (00:58:56)