Revealing mistake: After Vada runs out of Hilary's shop, she and Nick are walking down a crowded street. If you look around them you can see the same extras walking back and forth.
Revealing mistake: During the Bicentennial celebration, two guys from the pit are supposed to be distracting the security guards by faking seizures. During the close-ups we can see that the security guards are all huddled around the guys wondering what's going on, and basically not on their guard. However, whenever we see a shot of the stage, the security guards can be seen in the background standing naturally and guarding the steps of the stage. This does not coincide with the shots of them huddled around the guys who are having the seizures.
Revealing mistake: Forced perspective techniques are used to make Martin Short appear to be a ten-year old in the movie. This occasionally fails, most notably when Clifford gets out of Uncle Martin's car, and he is walking down the airport aisle. In these scenes, he appears to be six feet tall.
Revealing mistake: At the beginning, when they have just robbed the bank, the fat guy slides down that shoot on the outside of the building as the get-a-way car pulls up to meet him. If you look closely at the road before the car stops, you can see skid marks left by the car in previous takes.
Revealing mistake: When Shame calls the department store from the payphone, he makes the call without putting money in it. He just picks up the phone and dials.
Revealing mistake: When they are stopped after curfew by the Mohawks, Hawk jumps at the window and orders them to give them 50 bucks to go on, and they accept credit cards. When saying this, you can see the dividing line between his real skin and the fake head cap that supports the actor's fake hair.
Revealing mistake: When Preston crashes into Quigly in the bowling ball to send him into the pool, you can both see and hear the launchpad that actually launches him.
Revealing mistake: When Reggie and Tim the sheriff's son are in the funeral home and get confronted by the two black women, the silver ball comes to attack and kills one of the women. Tim saves the day with a revolver, but when he spins the cylinder before firing, you can see all of the cartridges in the gun have already been fired: dimples in the centre of each casing.
Revealing mistake: When Yvonne comes home to find her ex-husband in her apartment, he comes out of the bathroom with a towel around his waist. He then goes and sits on the couch. At one point he uncrosses his legs and you get a flash of his underwear he's wearing underneath the towel.
Revealing mistake: When Blankman is using his homemade grappling hook, you can see that the string is attached to the top of the invention and turning the handle isn't doing anything as he's simply being lowered.
Revealing mistake: When Alex throws Banes at the lab, you can see the stunt double falling for him.
Revealing mistake: When the tiles pop off the wall near the beginning, each pops off right in the middle. The nozzles squirting out the water are obvious.
Revealing mistake: When the doctor is cutting the forehead, a red tube to release fake blood can be seen behind the scalpel. (00:30:12)
Revealing mistake: In the overhead shot of Eddie flipped back by the plank decking him in the jaw, look when he lands; the modest impact makes a chimney supposedly made of bricks wobble conspicuously. (00:26:05)