i read this on a whim, i was looking for a gory horror at the time, and this happened to be under that genre on the site i was reading manga on. before i started readign i skimmed the reviews and read the word "homo" a few times and that made me excited with my yaoi addiction and what not but, once i started reading I was left with something much more than the dumb bulk yaoi-horror that i was expecting, something really deep and thought provoking!
once i started reading, I couldn't stop. I spent a whole day, reading 10+ volumes of this manga, i was completely absorbed. There's barely any gore but the tension set in this manga had me sitting at the edge of my seat a few times. While reading this manga, I was happy, angry, sometimes absolutely disgusted, it even made me teary eyed, once.
What I ire about this manga is, first, the original concept, the homunculus. I really like how the artist decided to interweave all the definitions of homunculus together in this story, the somatosensory homunculus, the fetus... etc. You can really tell he did his research and spent a long time mulling over this manga. Also, the way he did his characters, they are demented, unwhole people, and as readers (or more, human beings) we can relate to this in many cases, nobody is whole, everyone has their own shortcomings and complexes (though never as many complexes as the main character haha).
The only beef I have with this manga though is that... it was kind of hard to swallow, the whole seeing homunculi thing. part of me wanted to laugh it off, it was really hard to take seriously in the beginning, and still is (and was) hard to explain to my sister when she wanted to know just what was the hype about this manga that i kept on calling "genius, genius"