To help you answer these questions, let's reflect on how German expressionism worked in films during the 1920s. Expressionism is especially focused on fears, desires, and internal conflicts, but it doesn't present these in a realistic way. Rather, it dramatizes these emotions and disturbances in a way that is visually powerful and even startling.
Filmmakers, for instance, used odd angles and perspectives in their films, even to the point of distortion. They created movie sets that mirrored these angles, often so exaggerated as to be physically impossible in the real world. Filmmakers also played with light and dark, introducing deep shadows into their works and emphasizing contrasts. One film critic, Lotte Eisner, called these contrasts "Helldunkel" (literally, "light-dark") and noted that her chosen word describes "a sort of twilight of the German soul, expressing itself in shadowy, enigmatic interiors, or in misty, insubstantial landscapes."
Further, the subject matter of German expressionist films tends toward the strange and even horrifying. Stories are emotional and subjective with a focus on internal strife symbolized by external terror. Many storylines seem to have developed from nightmares, and characters must confront insanity, supernatural horror, and the deepest, darkest parts of themselves and others. Many of these films are silent, so the actors use dramatic gestures and facial expressions as well as onscreen words to tell the stories, but music is always part of silent film, and it adds to the dark, suspenseful atmosphere of expressionism.
Films in the German expressionist genre include the 1920 movie The Cabinet of Dr. Caligari, with its strong sense of the macabre and its insane hypnotist; the 1922 Nosferatu, a dark adaptation of Dracula; and the 1924 film The Hand of Orlac, in which a pianist loses a hand in an accident and receives the transplanted hand of a murderer.