The art of this anime is very unique but quite fitting for the topic and atmosphere, it feels fresh and dark, but it's not for everyone some people might find too motionless.
The soundtrack is nothing special in my opinion it could have been better, the ending theme is an exception to this given the fact that I find it quite catchy.
There is no real character development, you never really get to know anybody and characters are usually used as tools to produce a reaction in the viewer, the problem is once again a result of the length of the episodes and the kind of narrative.
With all this said, this anime might not be the typical horror that I'm used to watching, but it is spooky and engaging.
Overall it's uniqueness and quirky style make it worth watching, it's not a masterpiece but it is enjoyable and because there isn't any continuity between the episodes you can watch them with great lengths of time in between without having to refresh your memory, which is great if you hardly ever have time to sit and relax (watch anime).
