A perfectly made film that explores several existential themes: identity, choice, desire, eternal youth, and the wish to start life again. Zizek analyses it in The Pervert's Guide to Cinema (https://www.youtube.com/watch?v=j9O5lydOYDY) and it's one of Park Chan-wook's favourite films (https://faroutmagazine.co.uk/10-thrillers-recommended-park-chan-wook/).
The Pagan ritual scene reminded me of Mark Corrigan at Rainbow Rhythms.