Continuity mistake: During the first battle in the woods, the Union Regiment levels their un-bayonetted weapons and fires a volley at the Confederates. About 3 seconds later, without the order having been given, they are in hand to hand combat with bayonets fixed.
Continuity mistake: At the beginning of the movie (until Wasson's name appears in the credits), James Madison is writing on a paper copying from a large tome. Two people enter the room carrying a trunk. When he stands to go open the trunk and check its contents we can see that the book is gone from the desk. However, we see it again a minute later...when he picks it from those in the trunk and brings it to the desk. The first shot was a repurposed one. (00:00:50)