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The premise (woman moving to the countryside and falling into a hole) seemed weird and creepy, but in my opinion it was less creepy/scary than I expected. Yes, there are some weird things happening, and the author is very good at invoking this base-level creepiness throughout the (first) story.
Some of the creepy things involve the grandfather always watering the lawn day in day out, there being weird holes in the ground that some animal dug out, protagonist being bitten by a weird bug, everyone being very pale, no people ever being out on the street. Just a base level of these sorts of inexplicable and slightly weird things, really.
I liked the ending as well. I wish it had gotten a bit more specific other than „a lot of things the protagonist saw were just her imagining things, they actually never existed“. It did make for a nice twist, though.

The characters in the second and third story are the same, so I wouldn’t call them separate stories, but rather two chapters of one „story“. The second story, いたちなく, I probably enjoyed the most, the ending was interesting (a very short story-esque ending, but I liked it).

Language-wise, the author has some interesting quirks that made it a bit more difficult to read than your standard, say, 森 博嗣 or 小川 洋子. The author’s favorite expression is probably ～だの、～だの. She also loves listing several possibilities with ～か～か～か, which takes some time getting used to. But compared to other Akutagawa books, it’s not that difficult.