very detailed and nuanced - if not a highly cerebral (wink wink :-))- review of the film. as someone with very little knowledge about cinema and its visual grammar, i learnt a lot from your review. thanks.
from what i understand, the expressionist tradition in cinema wants to highlight/emphasize the inner subjective experience/turmoil of characters, and cares more about the visual projection of inner experience. And in order to do this, it often purposefully distorts the surface reality to underscore a particular point. Movies like Faust, Metropolis and Nosferatu comes immediately to mind - philosophical theme, existential, filled with harsh streaks of light & shadows, silhouettes, asymmetries etc.