*Spoilers*
After 15 minutes of writing i realised i probably shouln't spend the whole day here so I'll try to not say too much unnecessary stuff. What i like the most about this series and, well, the main theme of the series, is Nakoshi's journey to insanity. I really liked the way the author made it so that we were, unknowingly, experiencing the whole story until the last pages (right before the 1 year time skip) through the mc's perspective, making it so that it always felt like Nakoshi was nothing but a man who managed to get some kind of superpowers, but other than that he was just a normal person, all his actions seeming justifiable, and it was Manabu who was the problematic one, not understanding Susumu's actions. And well, even though Nakoshi's "sixth sense" was real, in the end that was the very thing that made him go insane, blinding his mind with the homunculi, and even if he did understand other people more than a normal person would, his mind couldn't handle it: he got to a point where his human mind was not prepared to get to. And, when seeing Nanako not having the same power as him (because, obviously, even before the surgery she was still just a normal person) he clinged to his idea of her, thinking she did have the same powers and the trepanation would bring them back.
It was right after she died that the author made us realize what it was actually going on: Nakoshi, a person who went totally insane killed a woman because he thought she would start "seeing him again". There was no coming back for him, and well, pretty much after the first trepanation he was gradually losing it, making it faster as the multiple surgeries came in. And that's what I meant when I said we've been experiencing everything through the mc's perspective: the final seemed very sudden and dark, when in reality it was only then that the story got a truly objective perspective, when Nakoshi, who had been living in his own world for one year already, got arrested.
The art was trully outstanding in my opinion. I don't think there's much else I can say about this.
The story was, as the rating says, very good, but i don't think it really makes the series stand out much.
Overall, even though i enjoyed it a lot, I still felt like there could've been more, and I kind of feel that at some points the author was putting more effort in the art alone.
Under normal circumstances i would probably give the series an 8 but, as i already said, the character's evolution was outstanding, enough for me to make it a 9