This movie is the epitome of film noir, with a classic detective narrative, revelations of a sordid past, and slowburn tension in a sleazy-yet-sophisticated setting. Unfortunately there is no depth beyond the face-value narrative. Still, this is a must-see for fans of the genre.
Closest comparison: It’s like The Maltese Falcon by way of Detour.
Setting: Noir
Plot: Noir
Tone: Noir