Fumiaki is a character that seems to be too much like the male leads of most harems. While that isn't a completely bad thing, as his nervous and hyperactive behavior is pretty damn funny, the moments where he is with Maya usually consist of him getting smashed in the face. This reoccurring gag is not funny, as we have seen this done in countless other harems, romances and comedies.
Another problem with the show is that it isn't scary. The scene where Maya was being attacked by the invisible... thing wasn't even creepy, as the show doesn't really seem to know how to execute horror scenes. For a show that has the name "occult" in its title, horror seems like something that will be necessary later on.
However, those flaws aside, the episode introduced plot developments that have hooked me to the show. The goal of finding the Nostrodamus key to stop the school from blowing up may seem like something that could be dragged out for 13 episodes, but hopefully the people making this will have the sense to make this tightly written with little filler episodes. (As the previous filler episode was pretty boring.)