For those not in the know, the book can be most succinctly described as follows:
A young man finds a manuscript in trunk in an dead old blind man's apartment. The manuscript is essentially an academic work dedicated to a film that does not exist within the world in which the manuscript is found and the myriad mostly fictional works cited in 400-plus often lengthy footnotes. And that film is a documentary about a prize-winning photographer (fictional in the real world in the book) and his house in which a hallway leading to an impossibly large, metaphysically anomalous black labyrinth suddenly appears.There's some more going on here, but the important part is the footnotes and the long tangential elements of the book that ultimately hurl the book into the realm of books that prove to be more trouble than they are worth. Sure, there is some merit to the book, but the labyrinthine task of reading the book and the psychological manipulation that Danielewski exacts upon his readers eventually cross the threshold into the realm of grating.
The great pains he goes to so that he can satirize academic criticism ultimately cost the book any chance it has to evade being an exercise in turgidity. While the wearying formatting may have been the goal for Danielewski, that doesn't mean the reader needs to be a willing participant. By the time the psychologically-suggestive, oddly formatted sections of the book arrive, the bullshit detectors are going off violently.
Any compelling sections of the novel are almost immediately undermined by pages upon pages of dull scientific exposition or faux academic criticism. Any momentum that could be gained is lost, and the reading experience ends up being an ultimately unsatisfying one.