Revealing mistake: During the sword fight in the castle a sword penetrates a glass panel behind which stands an armour. The armour is then pushed through the glass panel behind it. The first glass panel breaks in big pieces (probably the usual 'sugar' glass), whereas the second glass panel shatters properly.
Revealing mistake: As the invisible car creeps through the snow in reverse, the rear tires make tracks in the snow, as one would expect them to. Then the front tires go by, and the tracks do not change. It is impossible for the front tires to not have made tracks of their own, which should be visible, even within the existing tracks.