There was some promise in this film. But I have to say it got buried under poor writing, unimaginative cinematography, and a heavy-handed approach to film-making and storytelling.
Leto performed well, given the fact they handed him an impossible character. One which is supposed to connect with the audience on an emotional level, while also being a detached psychopathic killer. Believe it or not, there is a way to do this engagingly and 'correctly'. Leon the Professional comes to mind. They didn't do that here.
The overly-long transition scenes were a poor attempt at pacing. The acting rarely managed to deliver the goods, and the ending was trite and unimpressive. However, they clearly splurged on the scoring which was a welcome surprise. It's a Japanese lovefest all the way around, giving us all the the things traditionally associated with the country. But while I appreciate paying homage to an incredibly unique and beautiful culture, I don't think staining it with the horrific crimes of a small subset of the population was entirely appropriate.
Bottom line? I don't think this movie is worth your time. And I'm sorry to say that. It really had some potential, it was so unrealized.