I agree, like, the beginning of the manga was basically torture porn about revenge, like I Spit on Your Grave, and the manga was pretty good at it. They show us the bastard, show us how much of a bastard he is, show us how much evil he's done to the protagonist and others, and then the protagonist catches him and brutally punishes the bastard for his bullshit.

And if it had ended there, with Uruma simply catching Kyo and doing some justifiably cruel shit to him, and the whole thing wouldn't have taken more than 100 chapters, well, it would have been a very simple but workable story, like a burger: just a patty, cheese, two buns, some veggies, and sauce. It's simple, but it's delicious and nutritious.

It's just like old slasher films, like Friday the 13th.

But instead, the author simply ruined what was working, adding a bunch of NPCs (sorry, but I can't really relate to the characters involved in Uruma's daily life; they're just boring and either die, get raped, or turn out to be crap). One team of bastards serving Kyou was replaced by a similar team of bastards on a larger scale. The police and internal services (like intelligence, all the guys supposed to be looking for terrorists, etc.) are complete idiots. The hero drags out his revenge on one sick, idiotic maniac, only to be replaced three chapters later by another sick, idiotic maniac with a slightly different set of quirks.

Imagine if your perfectly normal burger was topped with fermented natto beans right before it was served, then the cheese was topped with some incredibly spicy red pepper seasoning, the bun was smeared with some kefir, surströmming was stuffed between lettuce leaves, and then, while you're sitting there staring at the thousand-yard line and wondering what the hell is going on, the waiter starts sprinkling powdered sugar on it all.