Revealing mistake: When the chipmunks and chippettes and getting ready for the balloon race, Jeanette walks up to Simon and asks him what route to take to Bermuda. Pay attention to Theadore; he's supposed to be in front of Simon handing the chest of dolls to Alvin who is in the hot air balloon. After handing him the chest, he dusts his hands and moves his head a little while doing it. If you look at his head, it seems to cross behind Simon's even though Theadore is supposed to be in front of him. Simon's face may have needed to be seen, but still a mistake.
Revealing mistake: At the end when Whoopi falls down the hill and hits her head on the rock, it's obvious that the rock is not real, since the rock moves very easily considering its size.
Revealing mistake: At the end of the movie, the trio arrive at the oil fields, crouch behind the rear of a car and Axel picks up some red dirt, explaining that it's the same as what was on Bogomil's shoes, and the horse. It is obvious that the crew just spread a small area of red dirt around for the shot. The majority of the area is regular brown dirt.
Revealing mistake: After CD has swoon Roxanna for Chris, Charlie falls out of a tree in front of the old ladies. If you look close you can see a darker patch of grass that CD falls in. It's clear it's placed there as a soft landing pad for the stunt man to hit.
Revealing mistake: When Marisa has her back to her window and you see Mason tossing out his paintings you can see wires attached to the paintings.
Revealing mistake: When the plumber is climbing out of the very snow covered well, the snow on top never shifts - an impossibility considering the actor's size and weight. The snow on the ground moves as expected. (01:05:10)
Revealing mistake: When the boys shoot the flaming arrows at the workers tent, it's painfully obvious they land in spots covered in fuel.
Revealing mistake: When Harry screams through the windshield of a car you can see the actor's mouth and teeth inside of Harry's mouth.
Revealing mistake: During the shots of Phoebe and Frankenstein as the vortex is open, watch the kids by the church in the background; they just rock back and forth over the railing to give the impression they are fighting not to get pulled in.
Revealing mistake: There are times in the movie when you can tell Bobo's beard is fake such as when Penny's giving him a drink from a 7-11 and it's peeling off near his right ear.