Sweet Jesus, Christopher Lee's portrayal of the monster. The version played by Boris Karloff wasn't exactly a saint, but it was still a largely sympathetic and even tragic creature that had no shortage of Pet the Dog moments. This version is a barely sentient killing machine that doesn't even hesitate to turn on its own master.
The monster's appearance is absolutely horrific. The Universal version certainly made for an iconic design, but few today are likely to be scared of it based on its appearance alone. This one genuinely looks like a decaying corpse that's been awkwardly stitched together after death. Just a little more blood and it wouldn't look all that out of place in a Lucio Fulci movie.
The monster's murder of the blind man. Considering his condition, the poor old man never had a clue what was going on, and was utterly helpless to avoid his fate. The fact that we don't even know what the creature did to him makes it worse.
The fact that monster's only purpose following his initial death is to be continually resurrected and forced to obey the commands of a madman like Frankenstein.
Arguably even scarier than the monster is Victor Frankenstein himself. Traditionally, the character is usually portrayed as a misguided but ultimately good-natured scientist who simply found himself meddling in areas he shouldn't be. Peter Cushing's take on the character is an absolutely despicable monster with outright sociopathic tendencies.
During the initial flashback to his younger days, Frankenstein seemed like a decent enough young man, if a bit obnoxiously full of himself. When he see him a little bit older, something just seems off about him, as though there's a certain darkness lying just below the surface. Then he begins graverobbing, and soon stooping to outright murder without a care in the world.
The maid's death. The shadow of the creature's arm reaching toward her is creepy, the shot of his face when she turns around is unpleasant, and Frankenstein locking the door to prevent her escape and ensure her death at the hands of the creature is horrifying.
As with the blind man's murder, we don't even know what the creature actually did to her.
A minor example, but the opening scene depicts a priest visiting a prison to speak with Frankenstein. While there, he passes multiple inmates begging to be let out or forgiven. The last of these prisoners, however, simply roars like a wild animal. What the hell kind of prison is this?
