Mediocre at best but still interesting enogh to keep me reading.
Story: ince this is a collection of stories in each volume and each one acting as a stand alone without any real chronology. Some are better than others, some have clear allegories and messages, some have none. All in all it's quite random.
Art: Again reasonable. The style is actually pretty clean but nothing outstanding. There seems to be a bit of unintentional repeating of faces though.
Characters: Again since this functions as a collection very few of the characters have a chance to be defined in depth or in anymeaningful way. This may be deliberate though since these events are taken from teh POV of the titular character and if nothing else his best trait concerning the other characters is unconcerned and neutral.
Not a bad read over all but there are certainly better. I'm not quite sure this manga even qualifies as horror but considering the age... it may well have.