It should be extremely difficult to play on all the themes Stoker awakens within Dracula so the best form of adaptation would be to borrow such themes in a way to create a new story. Nosferatu does this splendidly, with its play on shadows and using the technology of the day to play with the negatives and light exposure. Because the genius lies in the filmic technique and less on the storyline let's focus there.
To begin, the music score follows the progression of the plot. There is a theme for Johnathan and another for Nosferatu, which does what it means to do, which is to scare the wits out of the audience. The music helps in conveying the idea of spectatorship because the music that signifies Nosferatu is invoked before he is actually seen so there is always that idea of being watched. The techniques used just to portray Nosferatu as a creepy monster are amazing. For one, he has big hands and is an extremely skinny man. To help this, when he walks his arms stay below his waist and do not move and his long legs barely move. It gives this idea of him gliding way before the techniques could be used. Nosferatu's confined movements give this idea that he is an extremely constrained character, even more so than his limitations to the light of day.
Instead of showing Nosferatu claim his victims straight on, the camera instead turns to the wall and his shadow instead is used to portray how he engulfs his victims. Besides Nosferatu, whose characters exists within itself, the other characters must be overexaggerated to portray emotion because the film is silent and text can only do so much. Within the light and dark motif differences are made between nature and civilization, between old and new and prisonment which is seen in various ways through the movie.
First there is the constrained nature of Nosferatu himself, and the physical imprisonment of Renfield, to the actual imprisonment of Johnathan, to the figurative imprisonment of Nina. There is also the dichotomy of movement and constrainment which is portrayed in various ways from the wagon speeding to the castle, to Nosferatu's ability to barely move at all, to Nina who is later entrapted in the room while Nosferatu is watching. Happiness is portrayed through movement and likewise fear in this film is known to barely move at all. To help this idea of entrapment, a circular lens is used. Also, transitions are the old familiar circular fade in and out. This film is the starter to other Dracula films that follow similar portrayals of shadows, light and staggered movements.
Overall this film is an example of older movies that pay alot more attention to detail to get the point across. More recent 19th Century British films do not do fairly as well because emphasis sits on the sexual or romantic. Usually, until Dracula, the romantic which was this whole progression of propriety to sexuality and bizarre.