Oh uh, around the time I first came here I was pretty much obsessed with it, but I have to say it is one of the most unusual books I've ever read (and I intentionally seek out weird books). I really like how it tells the story in such a way that you largely experience it in almost the same way the characters do. When they're feeling claustrophobic, the type is set in such a way that it makes you (or at least me) feel claustrophobic as well as I'm reading it. I could go on and on, but I'll just say it was a fun read, it was terrifying, and it was difficult to get through yet very rewarding once you do. Not that it answers ANY of the questions it raises. The letters in the indexes at the end from Johnny's mother scared the fuck out of me, and I'll say no more as to that. Bit of advice, don't trust anything Johnny says, or anyone else for that matter.
As a side note, a quick search on youtube makes it obvious that HoL lends itself well to kinetic text montages, though I've noticed surprisingly few attempts to recreate the 5 1/2 Minute Hallway video.