'Fudoh' shows was based on a manga and it shows. The aesthetic of violence sprinkled with zany moments and some very otaku specific weird elements make that very clear. But it is still a self sufficient movie and a very unique one at that. It launched Miike as an extravagant director of great caliber.
The cult appeal assures it something a niche place in exploitation and revenge cinema. Plot-wise 'Fudoh' is about the relentless pursuit of vengeance that justifies the buckets of blood, the child assassins, the vagina darts (it makes sense, even) and other diverse methods of killing. But it is also a story of personal charisma and a family drama. Miike's dark humor makes a few striking appearances such as when a half Korean character goes into a fit over kimchi prepared in Japanese style.
The full title points to a generational conflict and indeed 'Fudoh' is something of a rebellion against adults and their degenerate ways, a topic that manga/anime often insist on. But there is no bright eyed youthful idealism here. Riki and his companions are fully conscious that to carry out their plans they need leave a trail of blood on their wake. The hyper violence for which Miike is so well known is already fully articulated in this movie and it reaches levels of stylistic prowess in a few sequences, namely the shoot out at the beginning.
Above all 'Fudoh' is entertaining. Fans of extreme cinema cannot fail to appreciate it and in hindsight it is very curious given the predominance that Miike achieved with his career. As a movie that points to later developments it has a redoubled interest.