Continuity mistake: At the end of the film the Monster tells Dr. Frankenstein, to leave. The Doctor and his fiancee run off. The Monster grabs a lever and says "We stay, we belong dead." He pulls the lever which blows up the castle. If you look to the left of the screen as the roof is collapsing, you can see Dr. Frankenstein knocked out on the stairs. Seconds later they cut to the Doctor and his fiancee running to safety outside the castle. It turns out in the original ending Universal killed the doc, but it tested poorly with audiences. They probably wanted a happy ending so they did a new ending where the doc lived, but they could not afford to blow up that castle again.
Suggested correction: We see Henry Frankenstein leaning against the wall with his arms outstretched, bracing for the collapse of the watch tower.
Other mistake: It's the scene when Dr. Frankenstein's fiancee is being held hostage. To prove that she's all right, her captor allows her to talk to Dr. Frankenstein through a telephone type device. She's supposed to be tied up with her hands behind her back. But she pulls one arm from behind her for a fraction of a second, then tucks it back behind her again.
Suggested correction: While some may see this as a gaffe, consider this: Elizabeth is quite resourceful. She has been tied up in the cave for some time and has been working on freeing herself from her bonds, to the point of success. As Karl attempts to cover her mouth, she has a moment of panic and almost gives away how close she is to escaping. Remember, she does escape and gets to the watch tower just in time to make a plea to Henry to leave with her to safety.
Factual error: The movie's title is factually inaccurate. The bride isn't "of Frankenstein" (the doctor), she's the bride of Frankenstein's monster.
Suggested correction: First, that's not what constitutes a factual error. At this point in time, "Frankenstein" was commonly used as the creature's name. Even today, it's understood. And in the novel, Frankenstein was never a doctor or held a doctorate of any kind. So, based on your faulty logic, it's a factual error to call him "doctor."
Suggested correction: In addition to the other corrections, the word "of" in the title can also be interpreted as meaning "from." This interpretation would allow the title to mean "The Bride from Frankenstein" or "The Bride Made by Frankenstein."
