Unfortunately this movie was partially spoiled for me by someone when we were discussing another movie, when he said something to the effect of "Oh, kinda like in Angel Heart", but I still enjoyed it.
"Harry Angel has a new case, to find a man called Johnny Favourite. Except things aren't quite that simple, and Johnny doesn't want to be found. Let's just say that, amongst the period detail and beautiful scenery, it all gets really, really nasty."
This is dark, complex, and very mysterious. It's also pretty spooky. Great acting(as expected), and great atmosphere. I'm definitely going to have to watch it again.