Why Memento is a true noir film - SPOILERS ALERT
Noir films have always, in my mind, involved detective-like work, and extremely dark themes - the underbelly of human behavior.
I caught something recently in Memento that I never considered before.
If the film is told in chronological order, then Lenny kills Jimmy, Natalie's boyfriend, and then afterwards, meeting Natalie, begins to stay at her house. Lenny also shares a bed with Natalie one night, after beating up Dodd.
Thus, it means Natalie has slept in the same bed as the killer of her boyfriend, and both her and Lenny are not even aware of this fact. That's very noir-ish in my book!!