This manga I feel is one that is really easy to simply not get into, in which case you simply miss the point of everything with nothing having an impact on you, and it'll probably seem terrible. On the other hand, if you do get into it like I did, I feel that it's one that can have a tremendous impact on you, in that this is the rare mangas that made me feel somewhat sick. Now this isn't because of gore or violence or anything like that, but because it has such a twisted viewpoint completely divorced from common sense and the hardest part about reading this manga is trying to slowly come to understand that viewpoint, wherein upon finally fully getting into it, it made me feel incredibly uncomfortable, which I haven't really experienced with manga before. It frames death, life, and love in such a strange manner, but slowly builds up to it and makes it seems perfectly reasonable, with the opposing views more aligned with common sense being the antagonists, and that's just a lot to take in at times. The story was a pretty gripping and wild ride for most of it. Kurosu and his pathetic self that slowly grew in a strange direction contrasted quite well with Miyaichi who seemed to have a divine like presence to her, and watching them and their relationship build up was immensely interesting. That's where the problem begins though, in that there is a point, a very obvious climactic point, where the manga should have ended, but they forced it onwards anyway. The reason it should have ended at that point, is that it was the culmination of everything that happened up to that point and should have been able to end things quite finally and in a satisfying manner in a number of ways. Instead, it continued onwards, in an incredibly directionless manner, where it wasn't clear where they wanted to take the story, and in the process ended up completely destroying the value of the amazing climax that had occurred. It felt pathetic to read to be frank, but it wasn't terrible enough to be unsalvageable, wherein if they went back to the spirit of the first half they could end it reasonably well. However, they botch that completely and end up pulling some moronic ending that tries to make things go full circle, but in the process, end up making the protagonists regret everything that happened. The manga gets you to adopt a completely different abnormal state of mind, but right before it ends it forces you back into normality, and hence makes it feel like everything was wrong, that there wasn't much point to any of what you read at all. I was invested in their relationship as twisted as it may have been, and in what they originally wanted to with it, so the ending completely destroying all of that felt awful. In a strange sense, while I won't say the story was happy, it wasn't despair inducing either when approached from the point of view it felt like it wanted you to adopt, so the ending being one heavily focused on being despair inducing, felt like a terrible way to end the series and once that I wasn't satisfied with at all. Ultimately, I would have to say this manga is quite unique and very strange, which has the benefit of being amazing when done right, as it is in the first half, but very easily becoming terrible when not, as it does in the second. The art was pretty good. 

tl;dr: A manga with a very unique look on society that works well for the first half but completely collapses in the second.