Revealing mistakes: As Colonel Dax is running through the trenches after General Mireau gives his order, a supposedly-dead soldier blinks.
Boom mic visible: During the first tracking with Dax in the trenches, the shadow of a boom-mike is visible.
Continuity: In the scenes of the men's executions the sky repeatedly shifts between gray and overcast in some shots to bright sunshine in others, noticeably changing the natural light, causing shadows and sun glare to appear and disappear from shot to shot.
Errors made by characters (possibly deliberate errors by the filmmakers): Near the beginning of the film Private Ferol, when asked by General Mireau, states that he has no wife - but while walking to the firing squad is crying on the shoulder of the priest that he will never see his wife again.
Continuity: After General Mireau slaps the soldier in the trench, he continues on to Colonel Dax's dugout and and three soldiers carrying a machine gun pass him. The same three soldiers still with the machine gun pass him again when he and Colonel Dax are looking at the Ant Hill through the binoculars.