I do have House of Hell and I should have added it to my interesting books list, as its the only one set in the "Real" world as such.
I thought it was a very good book, although I agree that you can get stuck in the dead ends and I have to admit I never really worked out how to finish it before I read the solution.. It all makes sense again when you read the solution through and there are clues on the way but many parts of it are hard.
I think that the only one next to that in diffculty is Crimson Tide which has a clever puzzle on it if you don't miss the words you are given.
