This got good just at the moment when I nearly quit. The opening is, I'm pretty sure, objectively bad: bad dialogue badly delivered in badly framed shots. It's also almost totally irrelevant to the rest of the movie and could probably have been binned. It was weird to go through that and then suddenly, just when I was about to switch off, find myself basically transfixed.
The rest isn't perfect, especially the end, but my god I love it, and there's really nothing else like it. It looks gorgeous, partly for the simple framing - owing something to Vermeer - and the butterscotch dominated colour scheme, but also the very prominent film grain, probably a result of the stock being pushed to keep lighting as simple as possible.
Though none of this is really quite it, at times it feels a bit like Rohmer and at times like something darker, like Mamet or Neil LaBute, but the point is probably that it sits somewhere in between and that's what creates the ache: the characters could be the vacillating lovers of one of Rohmer's bitter-sweet stories, but it all gets messed up and fully soured by capitalist alienation, in particular the alienation of sex becoming transactional.
The other thing its got that isn't in those other things is occasional subtle oddness in the generally paired-down realist visuals, something almost Magritte-ish.