Revealing mistake: In one of Pickett's charge scene the bayonets are obviously rubber.
Revealing mistake: In the scene where the women are laying in their bunks in the work camp and one lady is describing what she heard about the horrors of other concentration camps, at the end one woman puts up her hands to her face. You can see her fingernails are neatly manicured, something you'd think wouldn't be possible in a forced labor camp.
Revealing mistake: When Porthos shoots the assassin with a crossbow, he is a good distance below him. But when you see the assassin grab the bolt, it is straight in his body as if he'd been shot level.