This is the kind of movie where even though there are some noticeable shortcomings, they don't feel like they matter as much as they would in most other movies. Crows Zero kind of feels like a cross between a yakuza movie and a high school movie, and there's a decent amount of action in there for good measure. It takes place at a high school where classes don't seem to exist, and teachers I think are only visible in the first 10-15 minutes of the film. The school is just a battleground, really, with various factions and ambitious gang leaders (largely teenagers) all battling to "control" it.
It's a little strange how it begins sort of comedic and then decides it wants to be serious (albeit in a very heightened way) in the second half. There are probably a few too many characters to keep track of, but at the same time, considering the size of the cast and the pacing, the way they're all balanced is decent. It probably helps that most characters are straightforward, and like a lot of yakuza movies, they're all after essentially the same thing.
It's got a few action scenes throughout, and a pretty big one at the end that's a highlight. The wet, greyish mud a whole heap of people fight in reminded me of the opening action scene in The Raid 2 (2014). Like most times one film reminds me of another - and neither is the kind that EVERYONE has seen - it left me to wonder whether it's intentional, or just by brain methodically finding connections that aren't really there.