One of the more atmospheric reads on the site, I think. There's a real sense of unease throughout. The uneven sense of time and place definitely lends itself to some worthwhile effect. It's so hard to put into more words than that, and I won't bother trying.
The series was effectively "canceled" in chapter 7 when Tsubomi collapsed. I do wonder whether some of the complaints about disjointedness or unexpected developments could be lent to that...but chapter 1 stands out as telling an almost entirely different story than the rest. Very odd. Meanwhile, the betrayal especially felt like middle-school level fanfiction in an otherwise solid effort. Something did have to happen in a way, to push onee-chan to her eventual destination, but that was just too edgy and ridiculous.
There's a whole bunch of interesting subtext to this, that show off much better skills and nuance than perhaps the climaxes do. Tomoe's early ascent to adolescence (and the horror that causes them both). Mikage's fear of crowds signifying her inner feelings of abandonment. Mikage's disregard for her body stemming from early abuse. Their codependent relationship. I can't help but imagine Ogawa Maiko was studying up on what bad family dynamics look like, and what they lead to. There are a lot of quality crumbs here, but they don't ever feel explored to their fullest.
The best scene was definitely the aftermath of Takayanagi's confession. That "Something's not right" line hit me so hard, and how it relates to this chapter, their relationship, the previous chapters, and that other relationship...really nice storytelling. Of course, this is then abandoned in favour of that silly twist, but what can you do? Takayanagi best girl. That's all.