Continuity- The furniture in Basil's flat changes shape, color, and position in almost every frame.

Continuity- Mrs. Judson only took Olivia's Tam O' Shanter hat and scarf as she remained seated in Basil's chair, leaving her coat on. In the next few frames, her coat is missing and she never left the chair. Maybe she took it off when we weren't looking and then quickly sat back down in the chair?

Continuity- In the Chinese attire, after Basil removes the face mask, his neck appears bare. In the next shot, his high collar appears. It had to be hiding beneath the kimono and flipped up after Basil released the air of the fat suit.

Continuity- As Basil introduces himself to Dawson, he's holding the gun in his left hand. In the next shot, it's gone. Yet, as he says, "All in good time!" to Olivia and walks off-camera to the left, he quickly runs to the right and is seen holding it again.

Continuity- The entire Chinese costume vanishes from the floor after Basil removes it from himself. His hands and arms were light blue as he wore the suit, too. Were those long gloves?

Anachronisms (from IMDb Goofs): In the film Dawson claims that he was a member of the Queen's 66th Regiment. The film is set in 1897. The 66th Regiment was amalgamated into the 49th in 1881, 16 years before the events of the film take place.

Continuity- As Basil goes on about how he knew Dawson was a surgeon, that strange gun keeps disappearing and reappearing in Basil's hand in-between shots.

Continuity- As Basil aims the gun (which appeared in his hand again) into the pillows, you can see a coat hung over the blue sofa in the background. Later on, as Basil shoos away Mrs. Judson, a clear shot of the sofa shows the coat is missing. It reappears again as Basil crawls on all fours to find the bullet.

Continuity- When Basil shoots at Mrs. Judson's good pillows, bits of material and feathers litter the area. In the next few shots, it's perfectly clean. Did Olivia and Dawson clean it up? And where did the gun go for that matter?

Continuity- After the failed comparison of the two bullets, Basil goes to flop into his now clean red chair. He picks up his violin resting against it, although it was not there in many frames before!

Incorrectly regarded as a goof- It's been pointed out that Basil is playing the violin at first in the wrong hand, and then moments later, switches sides to hold it correctly. I'd like to think the mouse is such a genius, he can play the violin on any side he chooses.

Incorrectly regarded as a goof- The portrait of Ratigan on Basil's fireplace shows the professor grinning the entire time and only after Basil points to the picture, the image changes to him smiling with exposed teeth. This is England, you know, home to the world of Harry Potter? Basil (or a friend of his) must have purchased one of those magic pictures at a wizard's store from Diagon Alley!

Plot holes- Fidget appearing at Basil's window after Ratigan sent him to go to the human toyshop. There is no explanation to how he knew to go there, only that he needed to be there to drop his hat for Toby to pick up his scent. One way to save this from a plot hole is Fidget got a tip-off from another of Ratigan's henchmen. He was told the toymaker has a daughter and she might have gone off to seek help. The henchmen suggested she went to Basil, a very skilled private detective, causing Fidget to make a quick stop at Baker Street to see for himself. Another suggestion sent in by Wilhelmina is this: Fidget, on his way to the toy store to gather the things on Ratigan's "shopping" list, happened by Basil's flat, and unaware that Olivia was there, he showed up at the window with the intention of maybe startling or mocking Basil, just for a little fun. When he saw that the girl he was supposed to kidnap was there, he was naturally surprised.

Continuity- Basil was smoking his pipe and carried it out with him when running after Fidget. It disappeared when he retrieved the hat and never showed up again until the human toy shop. He must have put it in his housecoat pocket, but yikes, it was still lit!

Continuity- Mrs. Judson's appearance and disappearance. It's so strange, she suddenly shows up at the front door after Basil and Dawson run out, comforts Olivia very briefly, and then disappears in the next frame! In logical terms, she appeared after hearing Olivia scream, stands there to tell her not to worry, and as the camera is on Dawson saying, "The scoundrel's quite gone" and then to Basil as he says, "Ah-ah, but not for long, Miss Flamhammer!" Mrs. Judson had already done her exit back to the kitchen. Rather quickly, too!

Continuity- Fidget's hat disappearing from Basil's grasp. He ran inside with it, but as he removed his housecoat to put on his Norfolk jacket, the hat disappears. He later has it in his Inverness coat pocket to present to Toby. I can only guess he got the hat from where he tossed his housecoat on the floor, again when we weren't looking.

Continuity- Basil's Inverness coat and deerstalker appearing on the suit of armor when it wasn't there in many frames before. IMDb has this listed and I also caught it in the theater.

Continuity- The typical appearance/disappearance of pockets on clothing. Basil has a pocket the size of a drawer on his Inverness coat when retrieving Fidget's hat for Toby to sniff.

Continuity- Basil getting stomped on by Toby. Unless our hero is made of rubber, he would have been severely injured than just bouncing back. Characters can survive several degrees of injury in animation, thus the weight of Toby's paw is not the equivalent of, say, an anvil, so we would not see a bloody pulp of a mouse underneath.

Anachronisms- Dumbo, the Flying Elephant, can be seen as a toy blowing bubbles in the toy shop. The character was originally created in a children's book by Helen Aberson and published in 1939, forty-three years later of when this film takes place. However, with this being Disney, it's common for them to feature characters from their other films.

Continuity- After Fidget escapes with Olivia, Basil begins to smoke his...pipe? He retrieved it from his Inverness coat pocket, but how did it get there when he originally left it in his housecoat pocket, if he did at all? Maybe he's got more than one identical pipe?

Continuity- Back with Flaversham and Ratigan, the professor presents him to Olivia. Fidget's peg-leg has switched sides as she stomps on his only foot. He's been faking it all along and has two good-working feet.

Continuity- The disappearance of rips and holes in Fidget's ears after Felicia lightly feasted on him. They quickly grew back and restored themselves. That is the best solution to come up with.

Revealing Mistakes- When Basil and Dawson are examining Fidget's shopping list, there is no writing on either side of the paper. IMDb points this out at their site. I find this goof a little unfair because even though it's true, it was just easier to animate a blank piece of paper when shown at a distance. Goodness, at least we see the contents of the paper at a zoomed-in view!

Anachronisms (from IMDb Goofs): Basil is seen smoking a cigarette in the seedy bar. Ratigan is seen smoking a cigarette using a cigarette holder. The film is set in June of 1897. Although cigarettes were around in 1897 they were expensive and all hand rolled then, usually in either Egypt or Turkey. They would've been too expensive for low life criminals back then. Pipes and cigars were more common among the populace then. It wasn't until the 20th Century and the invention of automated cigarette-making machines that cigarettes became more popular.