Continuity mistake: Shoeshine is telling Jack to 'give the dog your food'. Jack throws him a rubber steak, which moves further away from Shoeshine in a subsequent shot. (00:35:00)
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.
Visible crew/equipment: When Cad and Shoeshine are sitting down at brunch, you can see a crew member reflected on the brunch.
Revealing mistake: When Jack is typing the fake note to get him out of PE class, he is not really typing. You can tell by looking at his fingers, he is just 'drumming' his fingers over the keys, hitting them as fast as he can.
