Revealing mistake: When our heroes are on the conveyor belt which carries the rocks towards the spinning saw blades, the rocks which get cut in two are seen to be cut before they reach the blades. (01:20:45)
Revealing mistake: When Charles Hawtrey picks up the formula in the Street of a Thousand Artisans, you can see that the cobbled street on which it has fallen is made of rubber as it bends with the pressure of his hand.
Revealing mistake: When our heroes are on the conveyor belt heading towards the saw blades, it's obvious that the conveyor belt on the other side of the blades is just a painted backdrop. (01:20:45)
