Revealing mistakes: After Markoff puts the first corpse back on the wall to give the illusion that there are many legionnaires on the wall, it is clear that the "corpse" is still breathing.
Continuity: John as a boy goes into the pond to get the boats and is wounded by one of the cannon. The wound is visible before the canon fires.
Continuity: It is night when Markoff and the others go into the barracks to stop the mutiny, but it is midmorning when they come out.
Continuity: Beau's hands change position as John leaves the fort and again when Digby enters.