Revealing mistake: When they are observing the waxwork figures, it's obvious they are real people just trying to stand still, as you can easily notice the "wax" figures slightly rocking or moving, or the props they are holding doing the same.
Revealing mistake: When Marquis de Sade gets hit with the hatchet and falls against the brick oven, it is obvious that the oven is not made from bricks because it moves when he hits it. It also moves when Mark puts his hand on it to use it to get up. (01:29:57)
