Haha, I've actually read the entirety of Narrenturm back in junior high, and then forgot about it entirely until now. If i remember correctly, there were either three books or three parts to the novel, and even though I enjoyed the first two, the excitement sort of fizzled out by the third one. It's not a bad work, IMO, but I enjoyed The Witcher series a great deal more.
Oh, I can definitely see how it wouldn't be the easiest book to get into. Truth be told, I don't even want to defend Sapkowski's writing in this case, because even though I mildly enjoyed it back when it was actually in front of me, I forgot most of the plot the moment I turned the last page. Now, speaking of fantasy novels that actually made me angry at not being able to get into them, Malazan Book of the Fallen definitely tops the list for me here. Not sure if there are any Erikson fans here on Hubski, but if there are I would love to know whether that gets better. Took me a book and a half to begin realizing that maybe it doesn't.