Continuity mistake: The hot knives that are set up in the King Lear scene towards the end of the film are sometimes smoking and sometimes not depending on the shot.
Plot hole: Edward Lionheart severs the head of theater critic Horace Sprout while Sprout and his wife are asleep. (Lionheart gave them both a knockout injection). Sprout's wife (and his maid)discover the severed head in the morning, and both scream and faint. But in the next scene, critic Perry Devlin retrieves his morning newspaper and then reaches for his bottle of milk, only to find Sprout's head perched on the milk bottle. How did the head get from Sprout's house to Devlin's place?
Revealing mistake: When Edward is carrying his dead daughter, it is apparent that she is holding onto him in case he drops her.
Revealing mistake: When Jack Hawkins punches through the door it is very apparent that it's made of very thin wood to make it much easier to hit through.