Nosferatu, starting the lineage of Dracula movies to follow, follows up on The Cabinet of Dr. Caligari as an early "true" horror film. It helps establish the monster horror film genre that will explode in the 1930's. But beyond the genre element, the film establishes an extremely interesting cinematographic style. You can see the lighting techniques of German Expressionism on full display here.
There's amazing black and white photography, with great use of contrast, allowing blacks to be crushed and be true black in the same frame as a bright almost blown-out highlight. The contrast really stretches and makes use of the full latitude of the film stock.
Additionally, the staging of the scenarios was extremely interesting, with lots of depth. There are many shots where the actors are blocked deeper into the set so that you're given the perspective of three dimensionality, as well as a sense of impending horror as seen below:
While Dr. Caligari had already prepared me for Nosferatu, this film takes the baton of horror film and pushes it further in terms of how lighting especially, staging, and pacing can create suspense and horror. Murnau used a metronome on set to control the pacing of the actors because the slower yet still consistent they moved the greater the build-up of suspense and horror at the impending doom. The movements do not come as a shock but rather a slow dread, which is even more horrifying.