This is the 608th most frequent Hungarian word.
különbség
Difference.
Here, 'különbség' means the contrast or distinguishing factors between two entities, which are the movies in the context.
A két film között nagy a különbség.
There's a big difference between the two movies.
In this sentence, 'különbség' refers to the observed distinctions or variations between the two pictures.
Észrevettem a különbséget a két kép között.
I noticed the difference between the two pictures.
'Különbség' in this instance conveys the variance or distinction in quality between alternatives.