This might just be my personal opinion but this series has a lot of difficulty in executing its themes and as a result, a good majority of the characters lack depth.
The two main characters are two children and they often behave like ones which is to be expected of them although it's usually to the hindrance of the quality to their characters and frequently reminds you of their lack of personality or even depth.
On the other hand, at almost every opportunity there is for one of the adult characters to have depth (which this Anime surely tries to give them) they almost immediately try to spell it out to the viewer which turns this show into such a passive experience that I had to go back and rewatch episodes due to the shiny lights on my PC being a far more interesting viewing experience.
Besides that, I feel as if the things that most of the viewers of this show would likely be captivated by are a few handful of things, all of which are 1) simple and straight forward characters 2) an interesting world that ties into its story concept and finally 3) the fact that its dark which it almost always seems to turn to the viewer in a subtle way and say "you do realise how fucked up this is?" which I'm pretty sure that if I said no the Anime would try to turn itself into Tokyo Ghoul and come off as a bit try-hard.
I'll give it a 7/10 though although I personally feel it more like a 6 just because I might not be the target audience for a work like this.
Now, do I think this Anime is terrible?
No
I do think that there's a great story here that you could possibly enjoy but for the more avid viewer, you might not find this Anime up your alley.
Though there's some enjoyment to be had with more casual Anime fans.
