Revealing mistake: When Erin gets into the truck, in the next shot the camera backs up a little and you can see that it's only raining on the truck.
Revealing mistake: When the Penguin is sliding down the zip line, just before he hits Batman you can see Batman throwing a punch at nobody, he is swinging at empty air.
Revealing mistake: When Lola screams and the glass clock smashes, you can see the small pellet that makes it shatter, go through the glass and then bounce off the wall. (00:20:40)
Revealing mistake: In the bike scene you can see that the intro biker is much smaller than Belle.
Revealing mistake: During the big gun battle right before the last fight scene, Riggs is shown driving a forklift, and knocking over some barrels on top of Wah Sing Ku, leader of the Triads. When the forklift does the 180° turn, you can see that it is not Mel Gibson, but an Asian stunt man.
Revealing mistake: In the opening sequence, when the robbers are on the zip line, two Chicago Police squad cars (white cars with blue markings), not Gotham PD (blue with white markings) can be seen blocking off Van Buren Street for the filming. (00:01:05)
Revealing mistake: The final scene is filmed in Brant Rock MA, and the weather is blatantly CGI. If you notice almost everyone is bone dry in a supposed driving rain storm. Look especially at the character perched on top of the submarine tower. For contrast note the "pizza delivery" scene where it is raining heavily and everyone involved is soaking wet.
Revealing mistake: Just after Madison says to the Angels, "Looks like one of the three amigos has gone adios" and Drew gets thrown by Madison, Drew hits the wall. For some reason, the camera vibrates.
Revealing mistake: In one of the final scenes where Stallone is hanging out of the Statue of Liberty, you can see that his "JUSTICE TATTOO" on his upper arm is a fake. You can see at the edge of the tattoo that it is glued on the skin.
Revealing mistake: When Melanie Griffith comes home from the jail, as she opens the door you can see there's no wall, it's just the door.
Revealing mistake: When Crewe dumps the car in the river, you can see the wire attached to it that was used to pull it out of the water. Burt Reynolds mentions it on the DVD commentary.
Revealing mistake: In one scene, the Penguin is making a "bat" shadow puppet on the ceiling. But there's no light behind his hands. If there's no light, there's no shadow. (01:03:45)
Revealing mistake: When Jack is hanging out of the truck you can see him standing on the hood of the car which Lydia is driving. At some points we get camera view from the back seat of the car. In some angles the mirror inside the car disappear. This is to prevent us from seeing the camera. (01:04:15)
Revealing mistake: During the end scooter sequence along the cliff tops, you can clearly make out wheel tracks stretching out ahead of Phil Daniels' bike, yet he hasn't been over that ground yet - these are presumably left-overs from a previous take?
Revealing mistake: When the sheriff's car is flipped upside down, the sign behind the car is upside down too, so you can tell the car isn't really upside down.
Revealing mistake: When Chris Tucker is found dead from an apparent heroin overdose, you can see him still breathing on the chair.
Revealing mistake: As Terry and Martine approach Le Sac shop, you can see reflections in the window of that shop of trees. This gives away the fact this was a custom built set (as shown in the extras) and not the real location in London. (00:20:05)
Revealing mistake: In a scene where Frog is riding with the Bandit, she's resting her head on the center gearshift console. Although they're supposed to be cruising down the road, the automatic transmission shifter is in neutral.
Revealing mistake: In the final scene as Doc tell Billy good-bye if you look up to the top right hand corner of the screen you can clearly see a jet trail in the blue sky. Certainly not possible in those days. (01:42:20)
Revealing mistake: When the Hummer is flying through the air, you can see that most of the underside of the vehicle is missing, the engine, transmission, driveline, fuel tanks, all gone.