The pacing of the story is out of whack. It feels like the first three chapters were all that the author wanted to write about, and everything past it has been filler because they didn't expect to keep the story going. The story had a bit of a survival game theme going on at first, but then it turned into a lite version of "Mysterious Disappearances" paranormal event solving.
Also, dear god the English translation from chapters 2 to 10 is lackluster.