Continuity mistake: As he's about to depart at the train station, Friedrich leans in to try and kiss Elizabeth good-bye. He's mere inches from her nose when the shot cuts, at which point he's suddenly standing more than a foot away from her. (00:16:00)
Character mistake: When Herr Falkstein introduces himself to Frederick he tells him he has come 5,000 miles to bring him his great-grandfather's will. The ancestor in question was supposed to be his grandfather, not great-grandfather. (00:11:53)
Suggested correction: Victor is Fredrick's grandfather, but not the one who died. Baron Beaufort von Frankenstein died, leaving the estate to Fredrick. Beaufort is his great grandfather.
Audio problem: When the Monster is tap-dancing to "Puttin' on the Ritz", the motion of his legs and feet do not correspond to the sound of the tap-dancing.
Other mistake: When they are removing the casket from the grave, the grave is just slightly bigger than it. How did they get underneath?
Audio problem: At the end of the movie when The Monster is shaking hands with Inspector Kemp, he pulls his prosthetic arm off. Inspector Kemp is heard saying, "Oh shit," however his mouth says just "Oh."
Continuity mistake: Frankie arrives at the door of the blind man, who welcomes him. Then there's a close-up of the monster from a bit far away where you can see his shirt and head as if he were alone; however, a frame later the blind man is right next to him, his head almost touching the monster's.
