When the blind man is attacked, the top button of the Creature's coat is unbuttoned in one shot and buttoned in the next.
When Victor Frankenstein throws the lamp at the creature, the close-up of the creature shows a belt over its jacket with a padlock in the center of the belt. In the long shots before and after the close-up, the padlock is on the side of the belt, on the creature's hip.
The puppy is clearly moving even before Victor determines it is alive by examining it.
The teenage Victor is tutored by Paul Krempe (Robert Urquhart), a man in his thirties. Later, Victor Frankenstein is a middle-aged Peter Cushing, who looks much older than his 44 years, but Krempe has not aged.
In the rear shot, the monster is strangling the Baron while holding him up in the air. When the monster releases the Baron he clearly steps off a stool of some type to make it look like the monster was holding him off the ground.
When the grandfather takes off his wood carrier and drops it on its side, the sticks don't fall out and it's obvious they are nailed to the carrier.
When Justine is creeping up to the Baron's laboratory, she is wearing 20th century high-heeled shoes.
Victor Frankenstein is often addressed as Herr Baron. Switzerland abolished its last remaining titles of nobility in 1798. The film takes place in 1860.
In the opening sequence, the sound of the priest's horse's hooves clopping is not in sync with the movement of its feet.
In the last 10 minutes of the film, just before Paul pushes Victor into a pillar when they fight, as the camera pulls back we see a boom mic shadow at top left of frame,
and then it hurriedly exits.
Victor tells Paul Krempe that his father died ten years ago, and that he has been the Baron since he was five. That makes him fifteen years old, but Krempe asks (apparently seriously) if he is looking for a tutor for his son. There is no way a fifteen-year-old could have a son old enough to require a tutor.