It's a pretty great opening, I am intrigued to watch it.
But what makes you say it is "one of the best openings ever" ? From a similar era Berserk comes to mind as another good example.
Nothing in particular, I just like this one. I guess unique catchy music and nice visuals that aren't too convoluted or hectic.
I don't like 99.99% of openings, so I'm pretty picky. Most suffer from generic overproduced music and generic visuals IMO. Sometimes one is great, but not the other. Rarely do they both fit together harmoniously like one unit. And many ops are often choppy, like playing a note wrong but for visuals. Even most of my favorite show's OPs suck. I'm not gonna give any examples, because I don't want to insult anyone's tastes lol.
I like the OPs of Dorohedoro, Girls Last Tour, Serial Experiments Lain, Origins: Spirits of the Past, Chobits, Ghost in the Shell: ARISE op2, Mieruku-chan, Tomo-chan Is a Girl, ofc season 1 Tokyo Ghoul, Magical Destroyers
Pretty sure I forgot a few, but that's mostly it.
Tokyo Ghoul, Magical Destroyers, Origin: Spirits of the Past are by far the best, they just hit different. Especially that last one nails the synchronization between the visuals and the music.
I don't really see a pattern in any of these, so not what I like about them, other than:
