Broadly, never been a fan of anime. Don't hate it, just never was my thing. But in the early 2000s I was at a LAN party and we were bored around 2-3am, maybe "later". A friend had downloaded this but not watched it so I said alright no one else is really up to game. It was an intense watch. I had no idea what I had gotten myself into. It wasn't a gateway or anything for me. It's just a solid piece of work. Haven't seen it since but the experience is sorta just stored away to be accessed from time to time to this day since it was just so different from anything else I'd seen. I have no clue how a fan of this style or genre would feel about it, but as a relative outsider it was really cool.
It's such a unique movie. I'm not a huge anime person either, but the screenwriting is so pitch perfect and the animation style is so unique. It's one that I'll be thinking about for a long time.