Revealing mistake: In the Forbidden Forest, HRH are introduced to Grawp. Just as the giant lifts Hermione off the ground, in the shot from behind her, Hermione's legs disappear below her calves; the digital lines are actually visible. Slow-mo is not necessary. (Only visible on fullscreen DVD.) (01:29:40)
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: When Nick is on the roof of the Jeep, the stunt double is visible - just look at his hair. (03:23:30)
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 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.
Revealing mistake: The first morning, when Robert takes Giselle to work, they enter atrium of the Time Warner Center (the well-known statue of the female Giselle admires is one of a set, the other is male), which is located at 8th Ave and Broadway, at the southwest corner of Central Park. Upstairs, when Sam tells Robert that she can't find where Giselle is from, and then when Giselle speaks to Phoebe, the very distinctive Johnson Lipstick Building (it's reddish and has three receding oval-shaped levels) at 53rd and 3rd is seen outside the window. The office scene is obviously not filmed at Time Warner, because it's impossible to be in an office at 8th and Broadway, on the West Side, and be next door to a building located at 53rd and 3rd, on the East Side. (00:35:40 - 00:40:35)
Revealing mistake: The scene where the camera pans the stadium about 3/4 of the way through the film looked like a scale model with a fake background.
Revealing mistake: In the market place scene, the DJ is playing and changing CDs. If you look carefully, you can see that none of the CD player's output sockets have cables connected, and neither does the power input socket.
Revealing mistake: When the chipmunks are singing 'How we roll' there is a shot of Ian with some people in a private room. The music continues to play as they listen and the stage is reflected in the glass, how ever the chipmunks, back up singers, dancers, instrument players and audience are missing. (01:17:40)