Revealing mistake: Near the end of the movie when everyone except for Peter dies. Lucy is supposed to be dead, but we can still see her breathing.
Revealing mistake: Underdog's first costume is supposed to be a felted down (the more accurate term would be fulled) wool sweater. When wool is felted the stitches lose clear definition and usually achieve a "felted" look. It is clear that the sweater in the movie has just been switched for another smaller sweater as the stitches are still sharply defined after it has been pulled from the dryer. This is especially clear around the U. No attempt to make the smaller sweater look "felted" was made. This refers to the original costume with the solid white U, not the second costume with the yellow outlined U.
Revealing mistake: When Troy crouches down on the rocks, and leans down to see his reflection in the water, oddly the reflection is not reversed, yet his hair is combed the opposite way. (Did the director actually think that if Troy's hair was combed the opposite way it would pass as a reversed reflection?) Additionally, when he crouches down, the bottom button on Troy's shirt is unbuttoned, but in the reflection (as well as in the previous and following shots) the bottom button is buttoned up.
Revealing mistake: After the military attack Sao Feng's residence, when Elizabeth is seen fighting amid the melee the black spandex-like shorts are visible under her robe as she kicks up.
Revealing mistake: When Dewey is singing the protest song about midgets in 1966, modern cars can be seen driving in the background.
Revealing mistake: When the Sergeant has the shotguns in the backpack on his back, and you see a close up of his face, you can see that the shotguns do not have triggers. On plastic prop rifles, the trigger is usually molded into the trigger guard in the pulled back position, and you can see this on these prop shotguns.
Revealing mistake: In the scenes where Riley is using his computer to look up information on the "SearchInfo" site, the screenshot used is of Wikipedia. (You can even see the "About Wikipedia" link on the left).
Revealing mistake: When Nick is on the roof of the Jeep, the stunt double is visible - just look at his hair. (03:23:30)
Revealing mistake: Although set in the 1960's, the school bus lettering was Arial, a font not invented until 1983.
Revealing mistake: Right after "Without Love", we see Edna answering the phone. If you've seen the movie as many times as I have, you'll see that this is a recycled shot from earlier when Mr. Pinky calls.
Revealing mistake: There is one shot where Andrea, whilst dancing to avoid the security beams guarding the picture, puts her leg through a beam but nothing happens.
Revealing mistake: When Rasputin goes through the wooden barrier at the water park it is a clear CGI. (00:50:20)
Revealing mistake: In the opening scene, the little girl pulls the cake over to her with only a few fingers which is near impossible. When the camera angle shifts and she lets go of the cake, it still wiggles as if she's pulling on it, showing that it's being controlled from the other side, most likely by an off-camera crew member. (00:01:25)
Revealing mistake: In the barber shop scene, the barber takes a chunk out of Farley's hair with the clippers. A bald spot is shown a few seconds later. In the next scene, the bald spot is gone.
Revealing mistake: When Jessica Alba is in the dentists room with the chipped tooth, it's very obvious she's wearing a set of false teeth over her teeth.
Revealing mistake: Seth is seen holding the alcohol-filled detergent containers, waving his arms and saying to Evan, "You bailed on me!" If the containers were truly full, or even half full, they would be too heavy for him to move up and down so easily. They were obviously empty.
Revealing mistake: Rachel slides off her panties while trying to seduce Harlan, and when she offers to let him "touch it", she parts her legs slightly and it can be seen that she's wearing another pair of panties.
Revealing mistake: When Will and Jon are doing their final skate and Will breaks his ankle and they have to switch position in the final routine, they are skating around getting ready to do it and Will lifts up his broken ankle so Jon can grab it. When he grabs the broken ankle, Will shows no sign of pain, but earlier when he tried to skate on it, he screamed in pain.
Revealing mistake: In the beginning when Nick gets a present from Fred you see that the background is fake.
Revealing mistake: Near the end, right when "little wonders" starts, Lewis takes a moment to look at his future family, Lucille, Frannie, etc. When there's a closeup on Lewis, his memory scanner reveals a reflection of no one in the gym, except for Lewis, even though people are supposed to be standing in front of him.