Continuity mistake: The Latvian and French mice in the Rescue Aid Society are in two different locations between shots. (00:06:25)
Continuity mistake: When Medusa is sitting down, after the gators catch Penny, her staff lays on her lap, and when she cries "You force them to like you...", the staff rod turns red for a shot - the same colour as her dress. The staff rod also differs throughout the film from being black to brown. This can be seen when Medusa hits Snoops and one of her pet gators with it. (00:43:40)
Continuity mistake: We see a group of mice walking towards the entrance to the Rescue Aid Society. Bernard is sweeping by the entrance. Two mice are just about to enter. In the next shot, the two mice are gone. (00:05:20)
Continuity mistake: After Orville lands on his runway, as he talks to Bianca and Bernard, his chin strap goes from buckled to unbuckled between different shots. (00:25:55)
Continuity mistake: The headlight that is attached to the left side of the windshield frame on Medusa's motorboat, jumps to being on the right side of the frame for a shot, after the female mouse says she'd like to hit Medusa with her rolling pin. (00:37:20)
Continuity mistake: When Penny runs away and is caught by the two crocodiles, the crocodiles are twice Penny's size. When everyone is back in the ship the crocodiles are only half Penny's size.
Continuity mistake: When Penny is trying to start the swamp boat Teddy is in the seat, but when Medusa shoots at her he is gone.
Continuity mistake: The comb being used as a ladder to get to the top of the bottle at the beginning changes from shot to shot, the number of prongs changes dramatically.
Continuity mistake: Bernard's hat constantly changes throughout the entire zoo scene. Before they enter, it's just a hat with no straps. Then, when he is running away from the lion, his hat is attached, then disappears completely when he is fighting with the umbrella and lantern. Then when they are running again, the hat is back to being attached but now chin straps tied. When they get out of the zoo, the hat is on with the straps hanging loose, not tied anymore. During this entire time he is in a panic mode to get away from the zoo, he wouldn't take the time to adjust his chin straps and there is no time between shots at the end for him to untie the straps.
Continuity mistake: When Brutus and Nero bring Penny back to the river boat, just as they enter the doorway, while Brutus is holding her upside down, she is facing Brutus. In the next shot where Penny and the crocodiles are inside the boat, she is facing away from Brutus. (00:40:20)
Continuity mistake: When Penny is first captured by Brutus and Nero, Brutus initially holds her by the strap in back of her dress. In fact, that is how Brutus carries Penny back to the river boat through the swamp. However, when the crocodiles return to the river boat with Penny, Brutus is suddenly holding Penny upside down by her underwear. There is no explanation for how Brutus could have possibly turned Penny around like that without releasing her just for a moment and preventing her from escaping. It even stands to reason that Brutus would not release Penny until he got her back to the river boat. Additionally, when Brutus carries Penny upside down through the door of the river boat, Penny is facing toward Brutus. but in the next shot when the crocodiles are inside the river boat with Penny, she is suddenly facing away from Brutus. (01:18:05)
Chosen answer: As amusing as that would be, 99.9% chance she was not hung upside down from her undergarments.