Claire Clairmont falls out of the rowboat in the opening scene. A few seconds later, as she runs with Percy toward the house, her clothes and hair are totally dry.
Near the end, primates are in a cage on the lawn. Lord Byron actually kept all of his many animals in the house with him. Only his horses were kept outside.
Dr. Polidori attacks Percy Shelley. Lord Byron then strikes Polidori several times across the back with his cane. A square pad is visible under Polidori's shirt, disappearing and reappearing throughout the scene.