Story: Amazing story that keeps you interested the whole way until the last arc which is bogged down by filler and being drawn out a bit too long. This score may increase or decrease in the future depending on if they animate the rest of the light novel series or not.
Animation: Absolutely top notch, Very polished and appealing, the people who animated this put a LOT of work into it and had a pretty nice budget for it.
Sound: I can honestly say this anime's soundtrack is one of the best out there, it's very effective in enhancing the mood of the anime as a whole. Children's Domain being my favorite song from the OST.
Characters: Aside from the main character everything is very well done in this category however you'll find yourself on many occasions annoyed the main character or even outright hating the way he is.
Overall: This is one hell of an anime with a few common issues that weigh it down. They stop the anime at an okay place to stop for a pause till the next season but there are no statements or evidence that there will be another season and this first season is basically a prologue of the actual story told in the light novel series.