Description of A Series of Unfortunate Event's visual style

Whilst some of the production aesthetics can be compared to steampunk, the visual style that series most notably mimics is German Expressionism; an artistic movement that began before WW1 but became prominent during the 1920s. Whilst frequently cited, it is perhaps a misnomer to describe an aesthetic itself as steampunk - it is more of a genre term that focuses on the machinery of circa 19th century British/European industrialization. Certain elements of A Series Of Unfortunate Events utilize steampunk-esque design of props, such as the many gauges and cogs of the VFD decoder scope and the brass and piston technology of Montgmery Montgomery's pseudo vault door.

Curiously, during the first World war a lot of foreign films/theatre were banned in Germany, which created not only a creative vacuum but an artistic echo chamber; the result was a distinctly German art form. This style focuses on artifice, the Unheimlich (grotesque), employs scale models for landscape shots and abstract shapes and angles, particularly in architecture and lighting. It was a movement that predated any attempt at realist cinema (whose inception is often attributed to Italian Neorealism).

Whilst film was in its early stages, it took many of its cues from the world of theatre; so all early film sets were shot in studio/stage conditions. Despite the obvious differences in camera positioning, you can see some of the trademark visual styles beginning to develop in the screenshot below, from The Cabinet Of Dr. Caligari (Robert Wiene, 1920)

In a clever example of Genre Fractals, the show itself draws attention to its inspiration by referencing both the visual style of German Expressionism in the movie 'Zombies in the Snow'

which was itself shown at the 'Murnau Cinema' - A direct reference to the most famous German expressionist Director of All time, F.W Murnau.