I pretty much agree with everything Daz said.
As for the ending… it was surprisingly short, and more surprisingly I find myself content with it. While the whole plot with the Beastar seems to be dropped, I like that we got a send-off to the most familiar characters. And of course Legosi and Haru finally getting together.
I absolutely adore this manga. It's been unique and insightful, sorta scratching an itch that a lot of other manga missed. I have high hopes for her next work so long as she keeps them shorter and planned out. I suspect that's what caused the failings of Melon's arc - she probably had a plan in mind for the school murder arc, including the ending. But then the series became a breakthrough hit, she had to continue and make up stuff as she went. It's a very difficult position. From the Melon arc my favorite chapter has to be 162, Melon's flashback of his mother. A great example of a chapter that's impactful the first time you read it, but then gets more layers upon rereading it. My least favourites have to be the ones when Kyu and San were introduced. Their introductions felt forced and underutilized, and some of Kyu's chapters were just... way too uncomfortable (you know the one).
But overall this is a manga I'm going to put on my bookshelf!