TL;DR Verdict:

Oneric *deeply* dark romantic comedy. Expect fucked up visuals and a view into kink as filthy. Protagonist is super unhealthy, but this is in the camp as “Secretary” more so than “The Piano Teacher”.
Now for a more detailed review…
Boy meets girl, boy obsessed over unhealthy behaviours, girl is attracted to his pain and feels connection through sadism, boy has midlife crisis connected to inability to cope with death of wife, boy gets a fucking clue and sort of emerges from cocoon of self destruction.
Unlike cheerful romps like “Walk All Over Me” or “Preaching to the Perverted”, this one is trying to say something a bit deeper about humanity, at least in the artistic tradition of an upper middle class, middle aged man having a full on melt down while getting laid.
Juha is a slim, attractive but a bit goofy heart surgeon who loses his wife in the first act. It’s important here to take the scenes as his fractured psyche/fantasy assembling memory- as he imagines/experiences trying to save her from drowning and being pulled back from joining her by the demands of caring for his toddler daughter.
Thus we see him as comparing himself to a caught fish, choking in the bottom of a fisherman’s boat. Early scenes are important to establish Juha as having redeeming qualities- it uses a lot of show don’t tell to let you know what is going on and you are about to watch him completely fall apart for an hour.
I cannot review this without spoilers, so you are duly warned that I will probably deconstruct this enough to spoil some of the shock comedy gags.