A true film noir, we have a flashback that starts this story of a how a man fell in love with a woman and how it led to danger and then that premise leads us back to the present where the man has to act. This film is more in the vein of Double Indemnity. The main character is a former detective private eye who falls in love with his mark. She is the true Femme Fatale. While there were other femme fatales Jane Greer really oozes the lethal combination of seductive and criminal where you just know she is going to lead you into trouble but you can't help walking right into it with her.
The lighting in this film is heavily chiaroscuro and has characters walk in and out of doorways into rooms literally amongst shadows. It's quite drastic the contrast between the darks and the whites in this film and the way that shadows are allowed to fall on whole sections of the set.
In terms of performance, Mitchum doesn’t talk like Humphrey Bogart, he's got a bit more of a drawl and thus doesn't come across with the same edge as Bogie does. He's a bit more of a gentle giant in a way and has less appeal in a noir honestly as such. I don't really buy him as a criminal. Kirk Douglas however is awesome as the villain. He's very suave and very charming in his role thus playing the dangerous devil beautifully.
The opening scene of the gas station is very reminiscent of the killers, these are the same tropes being rehashed and perfected through the Film Noir genre. You see how incestuous this genre really is with literal plot points, settings and character tropes being reused over and over again, perfected over the course of the genre's development.