highly-enjoyable trip which only reveals its structure on a rewatch

Rating: 9/10 (16 April 2015)

I've seen this film 3 times now: the first time, as it first came out, was an absolute trip of an experience (I may have been somewhat under the influence myself). It was very enjoyable, but I understood next to nothing.
Couple of years later I saw another Aronofsky: Requiem for a Dream. As the fella shares my first name (although relatively common, it's somehow rarely seen in the arts) I was all up for supporting his second film. Alas, it was trash, saved from a dustbin score only by how well-made it was technically, and mostly by Ellen Burstyn's stunning performance. 5/10 in the end.
Disappointed, I returned to Pi to find out if the hash was to blame for my enjoying it. Turns out not, I still really liked it, and this time followed some more of the story, tho' still felt slightly bewildered.
In the intervening 10 years or so I've seen The Fountain which was a boring pretentious fart of a movie, not redeemed by the interesting visuals (3/10). Now just recently decided on a third watch of Pi, and this time I understood the whole film: the concept, ideas, narrative...it's so clear now! Reminds me very much of my experiences reading (and re-reading) Zamyatin's We. Any work of art which reveals more of itself over time is worth something special.
Throughout all 3 watches Pi remained an excellent 9/10 experience. Best not to tell you anything about the story or characters, just that the:

acting is superb.

direction is dynamic and exciting.

high-contrast black/white is extremely effective.

use of sound is excellent.

concept is satisfyingly high-end.

And it's got Hector from Breaking Bad in it :)
If you enjoyed Requiem & Fountain, I really can't say if you'll like Pi. It's a difficult film to openly recommend as it is, and there's not much like it to compare to.
I'll say if you enjoyed Eraserhead, you'll probably like Pi.