To anyone coming for this because of the anime announcement, I highly recommend you to read it since there is a new group that picked up the series so we might get a consistent stream of updates for the next few days or weeks. The manga is a lot reminiscent of the early arcs of The Promised Neverland, Made in Abyss (not gory or as disturbing as it), and The Girls from the Other Side. It's the perfect mix between fluffy and creepy, with a good character progression. Every character has steady growth, with lots of moments dedicated to mind-games and planning given the structure and setting of the story.