Horrible. Depressing. I left the cinema feeling emotionally violated.
The premise of this film was really interesting, but in the execution the audience are really not given any chance to emotionally connect to the characters. It left me feeling both bored and disturbed in equal measure. No character development as such, the most hammy excuse for acting/dialogue I have seen in a film recently. There were some great moments in terms of cinematography and visual set pieces, but ultimately I felt these lacked meaning or substance and thus rang hollow. Reading some of the other reviews I can now appreciate some of the trans subtext relating to the central character, but don't feel this makes up for the poor writing. I don't normally like using the word 'pretentious', but I can think of no other to better describe this sludge.
Don't get me wrong, I enjoy the likes of Panos Cosmatos and other experimental psychedelic fare, but would describe this as a poor pastiche of his work. If you are expecting something similar - avoid. If, however, you enjoy the feeling of being slowly buried in murky emotional slurry, then you might enjoy it.