A brilliant step forward in visual storytelling. The Lewton Bus Sequence employs the power of disembodying people in a manner that creates suspense and heightens action by the feeling of missing information. The movie is classic for using film noir tropes of lighting and camera movement/angles, particularly dutch angles and shadows against a wall combined. There's stark contrast between the blacks and whites of the lighting and the use of shadows especially is far more heightened and blunt than 1930's horror films. This type of lighting seems to hark back to German Expressionism and The Cabinet of Dr. Caligari which would inform Film Noir's style a great deal.
The film is very compelling, wonderfully acted and shows the dated nature of gender politics at the time. The woman is completely ditched for not having sex by a guy we forgive for just leaving her for another woman who will. This again speaks to the relegation of women to subservient sexual objects.
This film is notable for shifting lighting and composition in a way that infers meaning and emotion and especially impending doom. That's most noticeable in the swimming pool scene where the lights go out and shadows on the wall mixed with eery sounds anticipate a monster approaching. This scenario of a woman being vulnerable and alone in a swimming pool with the lights going out and the shadows heightening the anticipation of horror is a template for films later on like Halloween, Scream, I know what you did Last Summer, A Nightmare on Elm Street etc...
There is also this combination of violence and sexuality in the horror genre that is fully on display in this movie that becomes a part of later 1970's and 1980's horror films where sex is mixed with the violence of the villain to be a form of almost sexual violence in the horror genre. That doesn't really take hold in the mid-twentieth century but this film paves the way for that combination of sex and violence to blow up going into the 70's.