The thing that really stands out for me in this manga is the level of creativity on display. Seriously. It's goddamned glorious, from monster designs to all the crazy situations our characters find themselves in. This is a rare and fascinating glimpse into an extremely inventive mind, and I guarantee you that some of these vivid images will stay with you. Crazy, crazy things happen in this manga that you will not soon forget, and some of the monster designs seen will undoubtedly crop up in your nightmares sometime. It's that remarkable.
Another great strength is the art. A lot of it is done digitally, and this creates a unique feel not seen in many other manga. Environments, faces, monster designs, everything looks pretty amazing, especially towards the end. There is the occasional visual clutter or stuff-up of human proportions, but overall the art is really really great.
I also liked the characters, which is something of a controversial opinion, given that many of the complaints regarding this manga has to do with the characters. Protagonist Kei Kurono is a complete douche-nozzle, but we see him evolve greatly and change as the story goes on, until he's a pretty great dude. Many other douche-bag characters exist, but I believe that these are deliberate social commentaries made by the author. He is trying to bring out the worst in people, highlighting the kind of scum that exists in society. I don't want to bring out any specific examples, but overall the use of characters in this manga is very good.
Now let's get to the story, which is the most bumpy element of this manga. At first, it was amazing. It genuinely felt like a horror to me, with shocking unpredictable moments at every turn. The social commentary was in full swing, and there were plenty of moments of complete badassery. I consider this the best stage of the manga, a kind of social horror that is full of moral choices and dilemmas that make even the reader question their own morality. The social commentary and badassery continue for a long time, but after a while you begin to notice the bad planning of this manga. Many story threads are picked up and then suddenly dropped, creating plot holes and too many unanswered questions. Things are left poorly explained or simply not explained at all. After a while, it feels like the author was really just freestyling the story. Sure, a lot of creativity and badassery remains, but it never recovers fully to the standard of the earlier chapters. I kept reading for the sake of it, frequently getting bored and not feeling the same kind of excitement I did before. Eventually it loses its horror edge and becomes more like a Michael Bay film in the last hundred or so chapters, which allows for some great action but overall is quite dull. Some extremely awesome moments still remain, but you'll likely be yawning frequently, despite the badassery on display. At this point the series has lost it's edge, becoming nothing more than dull gore and occasional sex.
Now don't get me wrong. This is still a great manga. However, given the length and the dullness of the later chapters, it does become kind of hard to recommend. This series contains some of the most awesome, creative monster designs, chaotic, mindblowing situations and really gripping, emotional drama, but it becomes increasingly more 'meh' as the series comes to a close. It's still pretty cool, just nowhere near as gripping as it used to be. Despite ending this review on a quite negative note, the manga's good parts are enough to warrant this a solid 8/10.
