PLOT/STORY: In one word? Confusing. But it's not thanks to bad panelling or story-telling. Instead, the blame lies on the strange, ambiguous personalities of the main characters.
ART: The art itself is very aesthetically pleasing. The horrid drawback? The emotions are HORRIBLY done. While the mouths of characters change with their feelings, the manga-ka can't seem to get ahold of how to tamper with the correspondence of eyebrows to emotion. This is a major reason for why the story ends up so confusing, simply because you can't follow what any character is even feeling. All you have to go by is the dialogue, and the lack of emotion cuts its understandability in half.
CHARACTERS: Yet another bog of confusion emerges. While characters can be given some personality traits after reading the manga, the reader is left unsure of why everything happened. When paired with the lack of emotion shown through art, these confusing characters end up seeming flat and unrealistic. Even if you ignore Murakami, who is obviously not very emotional and can be considered to have a weird personality type, Masaki isn't much better. His image is strewn everywhere, beginning as a kind-hearted peer and becoming some emotionless, almost robotic being. If only Murakami did this (go from emotion to apathy), then maybe the story could salvaged somehow. With both main characters acting this way, however, the entire manga is thrown out of the loop. Luckily, the less-important characters seem to have normal personalities, and it's much easier to detect emotion in them than in the two main characters.
A final note? I think that this manga could have been much better. Only two touch-ups would have to be performed: a change to make faces/expressions more emotional/human (pair eyebrow movement with mouth movement), and a simplification of at least Masaki's personality to give more insight onto his choices (some character development would do wonders). But the lack of these things takes much away from this series, which is why I painfully gave it the rating that I did.