Behavior offscreen, dialogue, tension, momentum. My favorite kind of film. One that demands attention but rewards with outstanding characterization with each person at odds with one another. Sort of in the vein of David Mamet but without the super snappy dialogue.
Masterclass in writing, editing. Love the scenes where someone won’t answer a question only for a cut to a separate confrontation that reveals that they did, in fact, spill the beans. This film is full of that kind of thoughtful editing— lots of little decisions contributing to the simmer.