ironic_onion’s review published on Letterboxd:
I've said before that the Doppelganger is the original horror movie monster and I think there's something to saying that its fundamental to the medium itself. The heritage of horror in film derives directly from early filmic attempts at visual trickery, and the early horror films adapting literature like Frankenstein (1910), Jekyll and Hyde (1912), and Student of Prague (1913), all built themselves around the visual trickery of doppelgangers. The medium fundamentally allows the manipulation of images in a way that stage productions generally do not; one could not watch oneself perform on stage. In some way, in its very production a film could create its own doppelgangers.
The titular Black Room is itself a form of visual trickery, being made entirely of reflective black mineral, a mirror creating even more doubles. The film is deeply concerned with the mutability of perception and performance. The existence of these doubles raises possibilities of this mutability, this multiplicity of potentials, but ultimately these converge once again, a termination of possibility.