Revealing mistake: In the scene where Shen is seen walking down the road as he tries to hitch a lift, you can see all the cars are driving on the right side of the road. However, in some background shots you can see the traffic moving on the left side of the road as it is supposed to in New Zealand where the film is shot.
Revealing mistake: Anytime we see the back of someone's head while they are talking, their mouths aren't moving.
Revealing mistake: There are several scenes (most notably when the group is ambushed at Mt. Suribachi) where the bayonets attached to the guns bend back and forth showing them to actually be rubber instead of metal.
Revealing mistake: When everyone first gets off the bus outside the hotel, Williams shakes hands with Margaret. If you look at his wrist you can see his real skin, not the prosthetic which is supposed to go nearly up to his elbow. It can be seen a little better in the next shot as well.
Revealing mistake: During the scene in the bow thruster room near the end of the movie, Richard Dreyfuss rushes to the thruster tunnel access hatch to open it. As he grabs hold of the wheel, the hatch and frame visibly move, exposing it as the lightly built set that it is.
Revealing mistake: You can see the charges to break the glass armor at the chest of the first guard when Violet kicks down in the vault. (00:16:30)
Revealing mistake: When Stewart is working on his laptop at the satellite dishes, it is very obvious that he cannot type. He is tapping the keyboard repeatedly with several fingers, without moving his hands. (01:18:40)
Revealing mistake: In many of the scenes, particularly when Michael Douglas is leaving the cafe, you can see onlookers staring into the camera. A possible explanation is that few extras were used.
Revealing mistake: They let us see the stunt double's face for the girl Steven Seagal is fighting in the ending Cathedral scene, and she looks nothing like the actress.