I think this movie might've made more sense to me as a 5 year old!
I saw this movie with my parents when I was about 4 or 5 when it was on TV. I had a lot of fragmented memories of many of the scenes with strong imagery. It wasn't until I was about 18 that I found out what movie it was and I could rewatch it.
The most fun difference between watching this as a kid is that you're like: "Suddenly winged man fighting giant Samurai? Sure, why not! Oh, spooky! Exciting!"
As an adult, while I guess I can follow it, somewhat anyways, with these surreal art type movies, there's such a tremendous amount of confusion and 'WTF' moments going on. While I happen to love movies like that, they are among the most difficult movies to truly understand. No matter, I can love them just as much, even with my mild confusion.
I gotta say wow, this movie is so well made. So much effort put into the practical effects and models and the sets, the style, all the wires and tubes and machines. It's beautiful!