Continuity mistake: Hannay is talking to the milkman inside the door. Outside the door you can see across the street, the two guys walking down the sidewalk. A moment later, Hannay goes toward the door and now there's the milk wagon on the street right in front of the door. When Hannay pointed out the two guys across the street to the milkman, the milk wagon wasn't there and the milkman is inside with Hannay so he couldn't have pulled it up.
Continuity mistake: There's one peaceful scene where the point of view is from a boat drifting down a canal in town. As the boat drifts, it passes by some sort of monument, and a very clear full-body shadow of the camera man and camera is visible against the monument.
Continuity mistake: After swimming, Tehanni and Maimiti exit the sea with bare behinds, but they are covered in the following shot.
Continuity mistake: At the end of the film the Monster tells Dr. Frankenstein, to leave. The Doctor and his fiancee run off. The Monster grabs a lever and says "We stay, we belong dead." He pulls the lever which blows up the castle. If you look to the left of the screen as the roof is collapsing, you can see Dr. Frankenstein knocked out on the stairs. Seconds later they cut to the Doctor and his fiancee running to safety outside the castle. It turns out in the original ending Universal killed the doc, but it tested poorly with audiences. They probably wanted a happy ending so they did a new ending where the doc lived, but they could not afford to blow up that castle again.
Suggested correction: We see Henry Frankenstein leaning against the wall with his arms outstretched, bracing for the collapse of the watch tower.
Visible crew/equipment: When Groucho enters the rehearsal area, the shadow of the camera is visible behind him.
Continuity mistake: At the climax, the hero's large, short-haired dog dashes down to the village. It is obviously male. After alerting the villagers and foiling the villain, "he" runs back up to the castle, only "he" is obviously female on the trip back.
Continuity mistake: Curly's shirt is stained with clay, yet he hasn't been hit in the chest yet.
Continuity mistake: When Donald Duck is holding on to Mickey Mouse when Goofy is dangling on the ladder, you can see there is a window underneath Donald, but when he has his feathers burned in the next shot, the window has disappeared.
Continuity mistake: When Minnie Mouse falls down on the pillow whilst attempting to skate, the pillow bursts and covers Mickey with feathers. When Mickey goes off skating you can see nothing surrounding the pillow, but when we return to Minnie later on, there are now a lot of feathers around it.
Continuity mistake: During Astaire's big number "Top Hat, White Tie and Tails," he produces an invitation on stage, sings about it, then crumples it up, and tosses it away. It must be nearby on the stage, but when we finally see the entire stage, the invitation is gone.
Factual error: In the movie version during a series of shots of African animals, there is a shot of a tapir. This is incorrect as tapirs are not indigenous to Africa. This is probably also present in the serial version. (00:09:45)
Audio problem: A native descends a rope to beat on a drum and signal those inside to open the door. As the native beats on the drum, his actions and the drum sounds become further and further out of synchronization.
Continuity mistake: For the early happy ending, Ellery Queen takes the jeweller by surprise giving him the pearl necklace, and the fella, incredulous, touches his breast. The hands swap position at the first cut. (00:07:25)
Other mistake: John Wayne is recruiting other victims of outlaw violence to assemble his Avengers team; he gives them handwritten notes saying, "Go to Hall's barn at ten o'clock tonight." Forgetting the fact that he somehow managed to find a dozen or more ace gunslingers with his same vengeance agenda in the vicinity of the same barn, it is obvious, looking at the two handwritten notes, that they were in fact written by very different hands, not by just one person. (00:12:50 - 00:13:25)
Continuity mistake: Before Little Kitty attempts to recite "Mary Had a Little Lamb", you can see there is writing on the blackboard behind her. When she makes her exit, the writing has disappeared, and when Ham and Ex appear, the writing is back again.
Continuity mistake: When Mickey Mouse is preparing to start the concert, you can see that he has a music book on the stand in front of him. When the band start playing in the next shot, the book has disappeared, and in the shot after that, it is back again.