I can see where the negative reviews are coming from but if you especially like the slice of life genre, this is one you shouldn't miss.
This manga will overwhelm you emotionally. It is tragic, lovely, sweet, painful, lonely and doubtlessly fulfilling. This is a true gem, one of those rare manga that will make a deep impression and leave you satisfied with the beautifully executed ending.
started off as somewhat awkward but by the second half it improved tremendously
It's really nothing much but what makes this manga what it is is the way in which it was done. It has an air reminiscent of the
peaceful loneliness in Natsume Yuujinchou but of course with more drama. The story flows smoothly from each scene and you can understand the characters' motives, confusion and frustration. Don't let the seeming angst/heartbreak detract you away from reading this from the early chapters. It will be worth continueing. (hint: there is no "tragedy" listed under it's genre on bakamangaupdates)
As far as my view goes, their developments are very well done. From our protagonist who slowly grew in character into someone with his own resolve to Shuuya with dealing with his way of caring and to Rin's acceptance. While Kana might have had terrible things done to him, it is perfectly understandable why he fell in love and why he could still continue to love. It can be somewhat painful to read(though I really enjoyed that..) but this story is definitely about forgiveness from more than one party involved. For the other two, saying too much would be a spoiler but I have to say that they have beautifully matured.
From the deep yearning which was misdirected into love in Kana and the pained manipulative love of Rin to the overly protective familial love of Shuuya, the combination gives a praiseworthy sense of melancholy. Subtly, the message that love can be cruel, love can hurt, love can be used to hurt and that love can bring happiness and motivation is slowly played out.
Overall, this is a must read. I haven't read any bl manga that could move me this much for a long while and going by the amount of bl I've read, it is an impressive feat and I think one who enjoy reading stories about different kinds of love will appreciate this series.