Continuity mistake: As the Ice Princess falls down from the skyscraper, it is clear she will not land on the lighting button, but she does. Between shots the lighting button moves closer to the edge of the stage too. (01:15:10)
Hamster
Continuity mistake: When Selina arrives home from work, she walks around and listens to her answering machine. She then has to run off to work. When she gets back from work a second time, the dishes and cups in the draining tray beside her sink have totally changed. (00:22:45 - 00:28:45)
Hamster Continuity mistake: After Batman pulls the wires from the batmobile roof, the wires disappear/reappear during the scene. (01:20:30)
Hamster Continuity mistake: As the Penguin is walking down the steps toward the podium, before Batman plays the messages the Penguin said, a man and a woman standing to the left of the podium swap places between shots. (01:23:30)
Hamster Character mistake: Bruce Wayne talking to Selina Kyle says that Batman probably saved millions of dollars in property damage alone. When Batman first saw Catwoman he didn't do anything to prevent the property damage before the explosion that she caused.
Athletic JasonContinuity mistake: When the circus gang first attacks, after Batman uses his Batmobile to take out of the two juggling guys on stilts, he opens this flat panel on the passenger side of the Batmobile to take out one of the skull mask wearing bikers. Before taking out of the second biker, he opens that same panel again.
Continuity mistake: The Penguin is getting vegetables thrown at him after Batman jams his speech on the steps. In certain angles he is closer to the banners behind him, while further in others.
manthabeat Continuity mistake: Towards the end when Bruce takes the cat, the wounds on his left cheek change from faded to fresh.
oswal13Revealing mistake: When the penguins emerge to carry the Penguin (character) to the water after he dies, the penguins are blatantly little people in costumes. Their "skin" crinckles unnaturally, and the spot where their arms meet their bodies is very flat and fake-looking.
Revealing mistake: When Batman is driving the Bat-boat, just after he dodges the two rockets the penguins launch at him, as the Bat-boat slams back down into the water in the background, the scale of the water-splash reveal that this effect was achieved using a miniature set and miniature Bat-boat model. The scale of the water splash, and the enormous "drops" that splash up give the effect away.
Other mistake: There are several biker clowns not beaten by Batman early in the movie, but they disappear for the rest of it.
Rob245Suggested correction: Not sure how this is a mistake, just because those henchmen were not featured later in the film.
wizard_of_gore On top of that, the bikers were wearing skull masks. There's no way of knowing whether or not they were still in the film unmasked later on.
Phaneron Continuity mistake: When Selina arrives home at her apartment, she is wearing a brown suit, and then rushes back to work. When Max finds her looking at the files, she is wearing a gray suit with a shawl.
Continuity mistake: In the opening, Penguin's parents look at the cage holding him. From the outside, his shaking is making the cage move slightly side to side. From inside, his shaking is not moving the cage at all.
Movie NutRevealing mistake: There is a shot of Batman driving the Batmobile around town late at night looking for The Penguin. In this shot, look at the cars parked at the side of the road. They are miniatures as well as the rest of the shot.
THGhostRevealing mistake: When the penguins launch the rockets/missiles in the end, watch carefully. In the second wideshot of the rockets launching (right after the bats begin to attack Danny DeVito), you can see two of the rockets hanging in midair, not moving. At the beginning of the shot, you can even see one of them spurting some fire. The rockets (attached to visible guided wires by the effects crew) got stuck in mid air right before the shot began, a few seconds before this second volley of rockets fire off.
Revealing mistake: When The Penguin (character) is first introduced, feeding the other (real) penguins, watch closely. While some of the penguins are real, it's blatantly obvious that some of them (particularly the ones to the left of the screen when Penguin says "Hi") are animatronic puppets, as they have very unnatural neck movements and don't waddle around like the rest. A few shots later, when Penguin says, "I believe the word you're looking for is...", you can even see an animatronic penguin on the left side of the screen that is unnaturally leaning slightly forward, yet never falls, revealing it's a puppet that was mounted to the ground.
Continuity mistake: When Oswald Cobblepot is in his crib as a baby, in outside shots the rubber duck on the string is swaying back and forth. In shots through the crib bars, it is dead still. (00:01:00)
Hamster 
