This is nothing like the derivative by-the-numbers anime that we see too much of. This is a imaginative story that delivers a unique blend of cuteness, humor and terror. The high production values show a team that really wants to deliver something great.
One thing (so far) keeps it from being a true classic. The season ended at a reasonably satisfactory stopping point, but this is the sort of quest story that demands a resolution that shows the end of the quest. It seems obvious that the team that produced the anime wants to deliver future seasons that will complete the story. However given the economics of the anime industry and the fact that this is based on an ongoing manga there is no guarantee that this will happen.