You might think it's not that good, seeing as most of the written reviews I saw on MAL give it a low score. There are plot points that are left unexplained or cut out events that would probably realistically happen (towards the end), but the pacing is good, it's funny when it wants to be and the characters served their purpose of making me think about life and death very well. The negative reviews don't like the goofiness, dislike some things being left unexplained (which I personally liked, because not every mystery in life gets an explanation, especially when it pertains to human behaviour), accuse it of being "cheesy" (this one probably surprised me the most), complain about their not being enough action (it's not a battle series) and dislike the amount of death or that kids might get killed (which to me is a positive, because kids get killed all the time in reality). I'll be vague, but there was an emotional scene that was, compared other shows, was quite long for what it was, which some used to as a criticism, but for me the fact it was longer than usual made me think more about how long I'd be willing to spend before giving up in said circumstances, which isn't something other shows achieved when showing the same sort of scene. All in all, if I wanted to go into pretentious edgelord mode and pick it apart I might give it a lower score, like a 5 or 6, because the sum of its impact was greater than I'd expect if looking at individual elements of it in isolation. Still would barely change anything, because for me it probably achieved what the creator was aiming for.