I really like this film, especially with my photography hat on. A lot of the imagery taken from the mind of the serial killer is actually based on surrealist art, and some of the cinematography is superb, e.g. the sequences filmed in the Namibian desert
Tarsem Singh's next movie The Fall is visually similar (though in another genre), so watch it too if you didn't already: https://www.imdb.com/title/tt0460791/
From the aesthetic/cinematography side of things, it did stick with me for a long time; I haven't re-watched it since the early naughties and I do remember lots of scenes. It is just hard to take in that some people might experience a similar internal imagery and the very slight possibility exists that they also act upon it.