Revealing mistake: At one point when the soldiers are walking through the jungle, one of them steps into a trap and is pulled up into the trees to be killed by Indians. However, if you watch this scene carefully, when the soldier (who steps into the trap) walks into frame you can see a wire already attached to his foot leading up into the trees. He doesn't step into a trap. (00:22:26)
Revealing mistake: When Paul Castellano is shot, there is a blood spurt shown from where the bullet hits, but the position of the gunman who fires at him doesn't match the direction the blood spurts. The gunman is across the street facing Castellano at an angle, but the blood spurt shown could only be achieved if the two were facing each other directly. (00:56:10)
Revealing mistake: Watch carefully during the fight scene between Billy and Rifki, you can see the stuntmen a few times.