After listening to the book a half dozen times or so, I came to the thought it's like poetry in novel form, the prose can be beautiful and horrid in emotions. Case is high as often as he can and he's the lens we see most things through so everything is a bit surreal. So I'm guessing that's agreeing with you calling it an art house novel it that's close to what you meant.
It's one of my favourite novels of all time, I only wish I read it when it was newer, only got it like 10 years ago and I was prime age to read it in the 90s. Oh well,glad I got around to it.