overall, its good. i'm not a fan of the art, its too boxy and childish, but I understand it want to convey the feelings of 'childishness' here. at least the characters always look cute, I especially like it when Misha press her cheeks on Kotarou, a little bump on her cheeks is shown and it makes her look incredibly cute.
the plot is very good. I think most of the things that happens in earlier volume that seems random, explained in the end. in most manga, excessive skinship is just part of the personality, but in this manga, there is a reason for a girl that come out a blue to be overly familiar with a boy. I like the ending, though a bit let down since its not as tragic as some commenters here led me to believe. I'm prepared to cry, but the ending is pretty positive to me.
I think the characters are quite good too. Kotarou have his own complexes and are able to be developed until the end. Misha is quite simple, but utilized well. I love the fact that Ten, a side character, also have a lot of depths.
this manga also get some extra points for having minor shotacon moments here. nothing overtly sexual that makes laymen's skin crawl, but still enough to make someone like me happy.
so all in all, good!