... I'm going to be blunt. It has been a while (think 2014) since any company has produced a nakige that compares to this one. The characters, their backgrounds, their personalities, and the setting all come together to form a story of deep affection, pain, and tears that had me crying more than a dozen times throughout the VN.
In terms of heroines, this VN's imoutos are the best. Shinobu is the twisted, obsessive half-yandere, super-capable imouto who adores her niisan (with good reason). Tsubasa is the honest, affectionate, straightforward imouto who is incapable of hiding anything. While the other two heroines kind of pale compared to those two, their routes are another story entirely.
I'm going to be straight... there are no bad or under-developed paths in this VN. The characters' emotional and real-life (to them) struggles are intense, engrossing, and emotional. Neneko's and Yuuka's paths are cases of the 'paths surpassing the heroines', a phenomenon that has become sadly rare in recent years, as writing quality has fallen drastically in the charage 'genre'.
Technically, Tsubasa's is the true route, but none of the routes were neglected in favor of hers, though I could have wished for an epilogue based a few years later for Shinobu's path (a matter of personal taste). This is a mark of the skill of the writer and the person who designed the scenario, as the fact is that in most cases where there is a true or central heroine, the other heroines tend to be neglected, at least in my experience.
The protagonist in this story will probably get mixed reactions out of people, if only because he is a bit angsty, especially when issues of parents come up. He has good reason, as he is a victim of child abuse (he doesn't hide this, and it is revealed within the first half-hour of reading). At heart, he is a good person, but he is very exclusive in the people he cares about and insanely protective of those chosen few. His obsession with his role as a big brother causes some big problems in Shinobu's route, but that is mostly because he is very hard-headed and straight-laced... the type of guy who makes a vow to himself and never breaks it, even in the particulars.
Story-wise... this is classic non-Key nakige fare. The protagonist deals with his own issues (to varying degrees) while doing his best for the heroines, the troubles and drama along the way designed to drag the tears out of you, though it all ends happily eventually. I was particularly touched by the healing that occurs in the protagonist in Tsubasa and Neneko's endings (through different methods), and I, for once, wasn't frustrated with the protagonist and heroine's struggles in Shinobu's path.
None of the characters' struggles felt forced or unnatural, the way many charage make them seem, which was impressive in and of itself.
Overall, this is a first-class addition to anyone's nakige collection, and it is definitely going to be stiff competition for my VN of the Month for May. I wept, I laughed, and I suffered along with the characters and out of sympathy for them. I come out of this VN glad that I played it, a rare experience for a person who is as jaded as I am when it comes to VNs.