As usual, Live Action has a different story, but this different storyline is not that crisp. Tatsuya's actor was atrocious in the beginning! I don't know if it's a Japanese thing to act like that, but they were awful. It's funny in manga and anime, but those expressions won't fit well with real-life actors. The Gang members were also styled in uniforms, which Kilihito doesn't have in the manga, but they added them for some reason.
The good part was that they added more screen time for Uncle and Aunty, they're quite wholesome. Also, Kazumasa Big Bro was cast perfectly. That guy nailed the role at 99% and minus 1 percent for sass. The extra fighting didn't make much sense as they were not logically thinking, I think Out manga is way better, and the characters actually behaved in more rational manner rather than 6 guys taking on 50 guys, which is atrocious.
I think the movie is solid 7, with some good scenes, but as a manga reader, you'll be disappointed.