There we go, I was struggling to put it into words. "Hostile formatting" definitely hits the nail on the head. But while that might be off-putting to some, and definitely doesn't make it an easy read, it's a big part of why I think the book is brilliant. You are not supposed to be comfortable reading it. Nothing about the subject matter is all that disturbing really, a few slightly spooky things, but nothing macabre or sadistic. But the formatting itself is what makes it unnerving. I think the dedication at the beginning of the book sets the tone perfectly:

"This is not for you."

The whole book feels like you are uncovering something that you aren't meant to know. Like reading a private diary put together by multiple schizophrenics who all glimpsed some small part of the true secret of the universe, all contained within a house that's bigger on the inside.