Revealing mistake: When Detective Frazier enters the bank and tries to get the jump on Dalton Russell, they get into a struggle and fall down the stairs. As they fall down, look at Detective Frazier's head. It is supposed to be bald, but it suddenly has a full head of hair. It's quite obviously a stunt double.
Revealing mistake: During the final conversation between Detective Frazier and Arthur Case, Frazier holds up his hand with the ring on his middle finger. It is pretty obvious that the hand was inserted into the scene in post production; the hand doesn't move in a natural way and simply looks out of place.