It's the only adaptation of this particular manga that I'd recommend. Both anime versions have serious problems, but this film's highly entertaining. I enjoyed it a lot. Ironically, I'd been a bit tentative beforehand, since Takashi Miike's live-action manga adaptations have been hit-and-miss, e.g. Yatterman, Ninja Kids!!!, Terra Formars, Laplace's Witch, etc. Fortunately, though, this material was perfect for him. Thuggish lowlife samurai, gore, violence and much killing.
It's fast-paced, despite the running time. That's what you get when you adapt a thirty-volume manga, but it works. It doesn't feel compressed. You don't go away saying "the manga was probably better". They've chopped out a lot, including some good chapters, but I agree with its decisions. (Some of the missing material was good because it was slower and talkier, while to be honest almost the entire second half of the 2019 anime can be painlessly deleted. My only regret is that this film can't live up to the original's deeper and better developed Rin-Anotsu relationship.) In fact, the film could arguably have afforded to cut more. There's an episodic middle stretch that some might find repetitive, with Manji and a succession of foes. Fight enemy, fight enemy, fight enemy.
It works because of its rough edges. It's portraying a violent, crude world of punks and swaggering shitheads. It's a revenge story that's deliberately inverting a lot of morality and standard imagery. "This isn't about logic or good or evil. I just want you to kill them!" Manji's an anti-hero who, by the end, will on Rin's word slaughter 100+ men who are, technically, good. He's a dick to Rin when they meet. Meanwhile, their target is polite, beautiful and repeatedly spares Rin's life.
It's also extremely violent. One of the downsides of immortality is having to pull yourself off swords, for instance. Limbs get severed, including deliberately by the limb's owner. Sometimes, the violence is even funny.
On the other hand, though, the film's sleaze-free. That's amazing, frankly. The source material gets extreme and Takashi Miike is no shrinking violet either, but this film has almost nothing. There's no nudity and no prostitution, unless you count one subtle line of dialogue. ("My face is my fortune!") The rape of Rin's mother isn't lingered on and happens offscreen.
I like how Miike handles the magic. This is a story about a cursed immortal samurai, yet the film's so grounded and dirty that your brain calls it "realistic"... but it includes a hallucinatory moment with three heads. One of them talks. I wondered, briefly, if that was a dream sequence.
The cast are strong. Takuya Kimura really brings alive the snarling, anti-social Manji. Hana Sugisaki is also very good as Rin... and, incidentally, she's playing Manji's sister in the black-and-white flashback introduction. Her two performances are so distinct that I went back and double-checked, because I wasn't sure. The oddest performance, though, is from kabuki actor Ichikawa Ebizou XI as another immortal. It's mannered and it takes getting used to, but eventually you realise that it really works and fits the character.
Hiroaki Samura (the manga author) rejected Hollywood offers for this story, but has said that Miike got it right and lived up to his expectations. It's a strong film. It can be brutal, but also funny. ("Please write me off as a failure. More food, please.") I'm glad I don't live in its world, but I'm very happy to have seen it.