The creature breaks into the Bergomaster's glass bedroom doors but when they're first broken only his shadow is seen and then they're broken more as he walks through them.
The creature enters the Burgomeister's bedroom through the balcony doors, but, earlier the Baron needed to tie some sheets together to climb down from the balcony. There's no way that the creature would have been able to climb up with those boots on.
At around 13 minutes as Dr Frankenstein and Hans are entering the festival some of the same extras can be seen walking from different directions in different parts of the town.
The burning tower explodes violently then crumbles to a pile of smoldering rocks. The mob is shown along with Hans and the girl watching it. Then when they show the pile of rubble again there's a huge cylindrical copper piece of equipment shown resting on the right side that wasn't there before.
When Zoltan hypnotizes the creature and tells him to sleep his head slowly nods forward as he passes out. In the next shot (shown from behind) his head is once again looking straight forward. The Baron tells Zoltan to wake him up and he leans forward face to face with him (in a close up shot) telling him to wake up only now the creature's head is now slightly leaning back with his face tilted up.
(in the flashback explaining to Hans what happened before) He needs to conduct a lightning bolt through the creature to bring him to life so to do this he deploys a special antennae which rises out of the roof then angles and points to the storm cloud. That positioning wouldn't be necessary as long as the antenna was the highest point on the house it would act as a lightning rod.
Frankenstein gets mad at Zoltan when they're drinking and slaps the glass out of his hand but there isn't any sound of it hitting the floor. Actually, Frankenstein snatches the glass from Zoltan, he doesn't slap it from his hand. He pushes the same glass back into his face a few moments later.
The heavy makeup on the girl is incredibly obvious, especially since they only put it on her face. Her neck, chest, and hands should have had it as well. As is, the rest of her visible skin is obviously a quite different tone than her made-up face.
This supposedly takes place at a time when the type of lighting is gas or kerosene lamps. Yet there are colorful electric light bulbs (festival lights) strung along the front of the bar when the bartender gives the drunk the "bum's rush" and they all go out immediately at the same time meaning they were connected to one switch (a characteristic of electric as opposed to gas or kerosene lights).
In the police station/jail there is a lamp on the desk made to look like a kerosene lamp but the electric wire can be seen coming off it leading down towards the front of the desk.
When Baron Frankenstein is arrested the wall in the room behind him has what appears to be a chunk of plaster missing from it when the wall should be stone.
Frankenstein tells Hans to "get away from here" so he and the girl vacate the burning castle. Outside they see the mob finally arriving with the two men on horseback among them. When Frankenstein stole the carriage further back down the road and raced it through the mob, the two men on horseback would have given chase and easily overtaken him way before he even reached the castle.
The "ice" shown is an obvious prop made out of cellophane. When it's shown being melted they drip some water on the top so it runs down to simulate it melting but actual ice would melt evenly all around and drip profusely off the bottom.
This film relies heavily upon James Whale's Frankenstein, especially in terms of using electricity to generate life instead of the chemistry in the original novel. Unfortunately, they forgot that Whale's classic also moved the time line from the 1810s of the novel to the 1930s, when the film was released. It makes no sense to combine modern machinery and electricity with 19th century scientists seen here.
Victor Frankenstein returns to his long-abandoned chateau to revive the Creature. He uses copious amounts of electricity in the process. But his equipment sparks well before the lighting hits the attracting element rod on the roof. Where the electricity that powers his machinery comes from is never explained.
The story that Frankenstein relates to Hans does not match the established backstory from the first two films. It is possible, however, that Frankenstein is simply lying.