Considering the fact that the studio that worked on this show mostly produces generic fanservicey shows, it's really surprising that they'd come out with something like this. It's one of the most unique anime I've ever seen!
Now, my ratings may seem a little harsh, but it's pretty true that the on-the-surface qualities of this show are pretty mediocre. And it's not that "it's so bad, it's good' kind of deal either.
But the thing that makes this show so different is that it isn't marketed to a general OR specific audience. There is quite a bit of nudity, but it doesn't feel targeted to teen boy hormones. There is quite a bit of gore, but not enough to make it horror. It genuinely feels like a story they wanted to tell.
Overall, this show is very enjoyable and pretty re-watchable as well, I must add.