21 (2008) - 9 mistakes

Continuity: When Prof. Rosa calls Cole, Terry answers the phone and places Rosa on hold. However, when Cole takes the phone from Terry, he does not take Rosa off of hold and proceeds to talk to him.

Visible crew/equipment: In the very beginning of the movie, Ben is seen riding his bike over the bridge in an aerial shot. Near the top of the screen, if you look carefully at the end of the bridge you can see a police barricade at the end of the bridge. It is there because the bridge is closed for filming.

Continuity: During the scene in which Ben is introduced to the card-counting group, several members are sitting at a blackjack table. There are cards on the table in front of them. In the first shot, the cards are face up, in the next, they are face down, then they appear face up again. While no one is seen or heard dealing cards, the number of cards on the table changes in several shots.

Continuity: The subway scenes between Jill and Ben show someone in a coat with black and white squares get on the train. However, a later scene shot throughout the subway car's window shows this same person wearing the same type of coat sitting down on a bench with a friend at the subway station as the train pulls away.

Factual error: Jill tells Ben that she has a suite at the Hard Rock and asks if he would like to see it. In the next scene it shows her looking out the window (presumably at the Hard Rock) and seeing the fountains of the Bellagio. This is not possible as these two resorts are almost two miles apart on different roads.

Continuity: During the first meeting with Ben, the cards that Micky deals alternate from face up, face down, and missing alltogether.

Other: In the opening scene, Ben is seen riding his bike over the Mass Ave Bridge towards Cambridge. A few moments later, he is seen coming over another bridge [possibly the Elliot] into Cambridge. There would be no reason for him to ride into Cambridge over the Charles River and then seconds later be riding into Cambridge over the Charles River.

Revealing: When Jill gives Ben the money after the first night, you can see it is just a $100 bill wrapped around a bunch of $1 dollar bills.

Continuity: When Ben is handed his earnings from the first night a five dollar bill is seen on the outside of the bundle. Moments later a $100 is on the outside.