Goofs

When the monster appears outside Elsa's window, it casts a nearly full-body shadow on the library wall, with one arm fully visible, but in the close-ups of the monster the arm in question is obscured behind the window frame. Later in the same sequence, Ygor pops up over the monster's shoulder, yet the shadow cast seconds later shows only the monster.

When Cloestine greets the Monster, she grabs his pointer finger in her hand, then starts to let go. The camera then focuses on the Monster, and her hand in nowhere near either of his.

Ygor seems to have been able to have his teeth fixed since the end of Son of Frankenstein (1939) although he has been sitting by the sulfur pit since the earlier film.

When Elsa is reading Dr. Frankenstein's notes, we see flashbacks of the monster being created, superimposed on the screen over the notes. When Elsa gets to the part of the notes that reads, "And now to find a brain," the flashbacks have shown the monster charged with electricity and brought to life and although in proper history, the brain was put in first the flashbacks are meant to be Elsa imagining the creation of the monster. Having never known about the monster she would not have known that the brain was first.

The first time we see the close-up for the wall plaque for "Dr. Frankenstein - Diseases of the Mind" outside his "mansion," it is hardly in such a place. If you look close to the left of the sign you'll see a ladder, wires on the ground, palm trees and a station wagon type of car.

The dramatic shadow cast by the monster's hand when first discovered by Ygor in the sulfur pit comes from a light source completely at odds with the overhead light shining down into the sulfur pit in which we see the monster encased.

The "iron" handrail on the steps on the stairway in the Vasaria town square wobbles visibly, revealing it's a flimsy wooden prop.

When the creature carries the little girl up to the roof, he is clearly holding a doll in the shots taken from below.

For some reason, after Ygor's brain is transplanted into the monster, the monster speaks in Ygor's own voice! There is no reason for this to be believable as the transplant did not include Ygor's vocal cords.

When Elsa is reading her grandfather's diary, it makes reference to his plans to create a monster, also called a creature on another page. Henry Frankenstein did not set out to create a monster/creature, he set out to create a man. It was only dubbed a monster after it came to life and proved to be dangerous.