Despite the plentiful ultra-violence and oft-inappropriate fanservice, it manages to be a very emotional - if also consistently extremely dark - drama. While it may be a show on naked mutants ripping people apart, some of the underlying dark themes and motives on all sides are all too realistic. While perhaps not in the vein of "high art" as it seem to (also) tout itself (mainly the intro and the clock symbolism), I found it a good - or rather tough, but cathartic - watch overall, which didn't overstay its welcome in its fairly short 14 episode run.
The gore and some of the nudity fits the animé well, but there's also some positively bizarre and at times almost creepy fanservice at display too, which certainly could've been lost for the better.