Revealing mistake: After Shiwan Khan's goon falls to his death and Moe is looking at the dead body, it is elevated up to the mid-section of Moe's body, indicating the the body was on a table or platform to get a better camera angle of Peter Boyle (Moe) observing the dead body. The shot could not have been accomplished if the body was at ground level.
Revealing mistake: The first time at the Cobalt Club, Wainwright gets a report of the Shadow, and plans a task force. Lamont's face goes dark, and he makes Wainwright forget about the Shadow. After the matter is forgotten, Lamont's face lightens, and you hear the chair he's in creak, giving away that he leaned back out of the light to make the illusion.