Revealing mistake: When they're trying to get rid of the bat at the cabin, they hold up a sheet to force it out of the door, however when they reach the door, you can see the bat being pulled up with string or wire.
Revealing mistake: When Stan falls into the dug-out at the baseball game you can clearly see the crash mat that he lands on.
Revealing mistake: In at least one scene, you can see the ruts that the filmmakers made in the greens to make Happy's putts go where they wanted them to.
Revealing mistake: In the middle of the movie, Roy is flossing his teeth by himself. In the mirror as well as when he turns around, you can see his hand holding the hook, if you look closely. (00:58:33)
Revealing mistake: In many scenes, particularly the dance scene in the bar, Michael's wings disappear and/or reappear. If you look closely throughout the movie, his wings are often completely gone.
Revealing mistake: When WD-40 is parachuting onto the island at the beginning, he throws a match through his parachute. As the shot changes, you can clearly see the smoke canister that was producing the effect of the parachute being on fire, swinging from beneath the canopy.
Revealing mistake: After the Martian who is dressed up as a women spits a finger in the fish tank a bit of the Martian's mask near its mouth is torn away. As she chews the nitrogen gum the human lips move but her real teeth don't. (01:04:20)
Revealing mistake: When Matilda telepathically makes the TV explode, you can see what looks like parts of an explosive hidden behind the screen.
Suggested correction: Clearly no sign of it.
Suggested correction: There is no view of the explosive.
Suggested correction: When the TV set explodes, it's a close-up of the screen and no device is seen. When it changes to a wider shot of the actual explosion, the glass breaks and some components of the TV set are shown. There is no way to distinguish between what is a component and what is, as you say, an explosive.
Revealing mistake: When "Roy" is punched in the water by Mr. Brady at the end, when "Roy" hits his head comes up and it is obviously not Tim Matheson.
Revealing mistake: At the end of the film Vanessa gets crazy because Bob kills her grandma, and she starts beating him up in the caravan, hitting him and throwing various stuff at him. Throughout the scene, Reese Witherspoon's' stunt double is really obvious. Her hair looks completely different!!!
Revealing mistake: After the second movie sign, when everyone gets into the theater and sits down, there's a very obvious cut, as all the characters cut immediately from the position that they sat down in to a completely different position. (00:28:05)
Revealing mistake: After Lucy discovers Mrs. Bradley in her bed, as she fights off and runs from Patricia, it is obvious that she wears knee pads for these shots.
Revealing mistake: When Daniel drives the van out the mall windows one window is left unbroken on the left side. All the windows around it are shattered.
Revealing mistake: In the mansion where the two flunkies are chasing the puppies that are to be skinned, one of them flies off the roof, through the stone battlements and crashes into a frozen pond. You can clearly see the stonework landing around him in the pond and bouncing/floating.
Revealing mistake: It's very clear they blew up a model of the buildings. The grass seen just before the explosions is way too long and is not as long when the characters are running away. Further, the truck and the barrels have disappeared at the explosion shot.
Revealing mistake: When Robert Stack introduces himself in the hotel room he says he is an A.T.F. agent, but the ID he shows says F.B.I. (00:26:45)
Revealing mistake: When taking the driving test Ashtray is driving down a street with on the left a parked white RV. After making a left turn, we see through the rear window he's driving down the same street.
Revealing mistake: In the scene where Romeo and Roy snap all the clubs other than the 7-iron, Roy drops his golf ball onto the grass. However, when he hits the ball, a white tee can be seen travelling up towards the top left of the screen. The tee can easily be seen but is much clearer in slow motion.
Revealing mistake: When the second helicopter is blown up you can see it is the same helicopter that was blown up the first time. The writing on the helicopter is reversed compared to the first helicopter. (00:21:10)
Revealing mistake: When the two FBI agents are thrown out of the car, you can see they are clearly wearing body armour under their clothing just for the purpose of breaking the fall. They look "fat" mainly on their torso because of the padding.