Continuity mistake: When Mickey walks down the stairs from the fountain, he walks down twelve steps. Later, when he tries in vain to stop the enchanted broom from coming down these stairs, there are at least fifteen steps.
Continuity mistake: As the crew of an English ship are crouched down on deck prior to a battle with a Spanish galleon, one of them stands up and moves to the other side. As he does so part of the background projection (ocean and sky) is shown on his back.
Continuity mistake: In the first fight scene aboard the boat, Ace's hat falls off his head. He then breaks through a door and falls down. As he stands up, the hat reappears on his head.
Continuity mistake: Near the beginning Harriet Vane produces tokens for herself & Lord Peter Wimsey of miniature handcuffs with one cuff "open to symbolise we're giving up on crime". She puts hers on as a bracelet. Immediately after & several times throughout the film it's clear hers is a set of closed handcuffs.
Continuity mistake: Searching for Spunky, Hunky skids to a stop when he sees a sign and looks up at it. Then it cuts to a close up of the sign reading QUIET Hospital Zone. Between shots, the sign becomes redder, and it appears the word Hospital becomes shorter, and other aspects of the sign change. (00:05:50)
Continuity mistake: Baxter and Beecher are riding in a horse-drawn wagon. As they go across a bridge, the train carrying the Marx Brothers approaches. Baxter and Beecher leap off the bridge, one jumping to the right and one jumping to the left, but they are side by side when they land in the river below.
Continuity mistake: When Papa Bear is drinking from the hot water tap after eating the hot porridge, the tap handle changes position between shots.
Continuity mistake: After the mouse is revived by water from Jasper, he goes up to the cat and you can see that the mouse's left hand is under Jasper's mouth, but in the next shot his hand is now near the whisker area.
Continuity mistake: When Porky is searching for his contract in the waste-paper basket in Leon Schlesinger's office, he leaves some paper on the floor. But when Leon tells him to go back to work, we cut to Porky and the paper has gone.