Revealing mistake: When the reporter dies on air, her face is contorted into the Joker's face. When the camera is in closeup on her face, the "dead" woman's bottom lip moves.
Revealing mistake: In the film's ending shot, the sky can be seen to flutter as the camera pans up, revealing a backdrop.
Revealing mistake: When Batman fires rockets at the Joker, none come out, instead a sound effect is used which cuts to explosions on the road where Joker stands.
Audio problem: Bruce watches Commissioner Gordon on tape at his party. In the first part, the audio is laid wrong and their mouths don't match.
Revealing mistake: When Vicki is driving car Knox jumps on, you can see it's a stunt driver in the wide shots.
Continuity mistake: When Joker comes to Vicki's apartment, Joker shoots Bruce and Bruce plays dead. As he plays dead, his right hand changes positions between camera angles.
Continuity mistake: The clown balloon was swelling with the Smilex gas, but when Batman steals it and flies it and the other balloons away, it's back to normal shape.
Factual error: The Bat signal at the end would not show up like it did in the film. In order to be as clear as it was, as well as visible, it would actually have to shine onto a surface, not just the clouds. They made this same mistake in Returns, but made it believable in the clouds (just not as sharp) in Forever.
Continuity mistake: When Knox and Vicki talk about Corto Maltese, she puts her left hand by her neck. Shot changes, and now both hands are on her neck. (00:13:51)
Revealing mistake: In an overhead shot, just before Jack Napier falls into the vat of chemicals, you can see that it is a stunt double, as he has significantly less hair on the top of his head than Jack Nicholson.
Continuity mistake: Notice The Joker's chin in the bell tower. It's covered in blood when first shown, a shot later it's suddenly just the center of his chin.
Factual error: It would take even a very strong acid a lot longer than a few seconds to eat through the thick metal bolts holding up the bell. (01:44:00)
Continuity mistake: Before and after his transformation, the Joker a.k.a. Jack Napier, has brown eyes, but in the flashback, he has blue eyes.
Continuity mistake: When the man is knocked out in the alley he changes positions between shots.
Other mistake: A lady is looking / smiling straight at the camera and crew at the start of the film when a character is trying to get a cab.
Suggested correction: The balloons were not filled with Smilex gas. The Smilex was in canisters that are visible underneath the balloons. The balloons themselves could have expended and contracted due to varying air pressure.
wizard_of_gore ★
Yes the canisters were on the underside. But if you look closely, when activated, the balloon began to swell, and holes appeared, releasing the gas.
Movie Nut