When the Professor first enters Count von Krolock's library, he puts his spectacles on at the tip of his nose, so that he can read some of the books' titles. He nevertheless looks right above his glasses, thus making no use of them.
After Alfred and the professor have escaped the tower, they walk down a hallway next to the ballroom and approach three vampires that are sitting with their backs to them. The left vampire is wearing a blue coat with spots. and the lady in the middle a cream colored dress. The next shot we get a good view of the dancing in the ballroom itself and the gentleman and the lady are both visible in the foreground of this shot. The lady sitting just in frame at total left, and the gentleman standing in the foreground totally right of the screen. The next shot we again see them sitting together with a third vampire in the hallway.
Abronsius and Alfred attempt to enter Count Von Krolock's crypt through an entrance on the ground floor, the crypt itself being located in the cellar. However, when apprehended by Koukol the Hunchback, they decide to go for a window entrance instead. To do this they scale the castle wall and enter a top floor window, with the crypt itself magically relocated to the top floor.
In the GB version, at 52:56 there's a daylight view of sky and mountains with no trees through the castle window as the hunch-back/vampires assistant lays down the coffin. At 53.20, after a cut, but still in real time, the view from the same window is now a night-time one and appears to be somewhat different with higher mountains, trees and no sky.
When the three escape from the dance, they come across bats hanging from the ceiling and the Professor starts studying them. When Alfred pulls him, the Professor stumbles across rocks on the ground which are obviously much lighter than real rocks would be.
Just before Count Von Krolock locks Abronsius and Alfred on the balcony he tells them they'd have great difficulty getting away from there, unless they had wings "like a bat". The Count suddenly loses his Romanian accent when pronouncing the words "like a bat".