I read up to latest scanlated chapter, ch4 or up to the second story (Act 2) so far. The art is undoubtedly superb. I also saw the raw and I see that this manga is richly told with about 5 stories, of which some characters' lives intertwined with another or others simply appear briefly.
From what I've seen (or understand) from the raw, there are 5 acts or rather what we may call arcs. *(Please correct me if I am mistaken anywhere here) *
Act 1 - Out of the 13 volumes, this is on volume 1. This is the story between students Yuma Mori and Suwa, and Kajima sensei. This is a quite melancholic unrequited love story but it was effectively told you'll finish reading it in no time. TBH, I don't particularly like the premise with Yuma but this a prelude to Kajima sensei's story.
Rating: 6 for the story, 7.5 for the pacing, 9 for the art (facial expressions are conveyed appropriately)
Act 2 - took up volume 2. This is an achingly touching story about Haruta Kazue, Seto Kanna, Mayama, and Asami. My heart went dokidoki on Mayama's guts and cleverness. Haruta is so sweet. Of course, my heart went dokidoki on his actions towards Kanna. This two guys are simply hot. Asami is slightly a bitch. She first broke what she said.
Rating: 9.5 for the story, 10 for the pacing, 10 for the art
Act 3 (volume 3) is the backstory of Kajima sensei and his fiancé.
Act 4 seems to take up volume 4-7 tackling on Mayama, the new girl, and a bit of Kanna.
Act 5 (volume 8-13) is a different story of classmates and childhood friends. The girl in Act 4 briefly appeared here.
I hope the scanlation will continue and finish this series.