Woah. I struggled for 150, make that almost 200 pages.
The writing is inelegant, and I truly pity the translator - probably some of the clunkiest constructions were fine in the original Japanese, but simply impossible to make elegant in translation. The result is hard on the reader.
So, why four stars? It's a good story, set in a well-imagined future, and some of the central characters are nicely drawn. The ideas come thick and fast, and are juxtaposed in a truly, surprisingly (to a Western reader who hasn't read much Japanese SF, anyway) original way - with the result that some sections that consist entirely of concepts and ideas I was well familiar with nonetheless left my brain buzzing with the implications from how Itoh links and deconstructs them.
Highly recommended if you're interested in deconstruction, self-aware storytelling, and meditations on death and cultural terror (it's in the title, really).