Revealing mistake: In the battle of Little Round Top, as the Confederate soldiers are backing down the hill there is one man walking backwards and loading his gun. Behind him another soldier aims his weapon and fires, shooting the first man in the side of the head. The man then ducks and waits for the smoke from the shot to clear and continues down hill.
Revealing mistake: There is one shot where the camera shows the battlefield with a large tree in the middle of it. You can see that the tree has been cut away to make room for a power line, which has been removed for the movie.