The first 74 pages of this are interesting, exploring the confused theologies of the characters Marek and Jude and leading up to an event that alludes to two stories from Genesis: Cain and Abel, and the Binding of Isaac. All very promising.
Then, the action moves to the manor and we're in something like Monty Python and the 120 Days of Sodom, except that that would actually be a funny movie. In fact, Sade himself can be quite funny. Moshfegh is not funny here, although she certainly tries. Boy, does she ever try.
In the end, we have an author who wants to take on the Big Themes but has nothing to say except the obvious: wealth corrupts, the rich exploit the poor, sham clerics lead people into deeper ignorance and error. Next she'll tell us that ice is cold.
Her technique is extremely uneven; Moshfegh is the kind of writer who can craft a beautiful, delicate simile and then use the next sentence to explain what it meant in the dullest terms. At some point, I started to think that she assumes her readers to be as stupid as the people of Lapvona. The book bleeds condescension. Her diction is likewise all over the place; a passage begins the ascent to poetry just to be brought crashing down by the most embarrassing word choice. This could be deliberate, of course. Perhaps Moshfegh also thinks that she herself is stupid, that everything is stupid, that the self-sabotage of her own work is a hilarious joke. I don't agree.
Some of the story's magical elements were interesting—I like the stuff about transplanting eyeballs—but in terms of weird enchantment, Lapvona has absolutely nothing on actual medieval literature; if you think this book is bizarre, you haven't read the Táin Bó Cúailnge.