They are enormous! The White Walkers- both in S1 and S2 -are played by the guy who is playing Gregor Clegane this season, and he's seven foot one! There was no doubt in my mind what was going on. I'm an avid reader, and I was curious to see what was going to happen- even knowing what Craster was doing. There is very little that can terrify me, the voice of a White Walker is one of the things that can. That icy, crackling snarl is so unique and so distinctive I knew what Jon was heading towards as soon as I heard it- my blood ran cold and my heart was in my throat; that scene terrified me because of I) The White Walker and II) It wasn't part of the book; I couldn't tell what was going to happen, but anything involving the White Walkers can't be good. I just want to know what they do with the kids now. I mean one moment the baby is screaming his head off, the next he stops, and the White Walker gently picks him up and carries him away. I wonder if they're going to discuss that next episode...
In any case- there were four key factors which gave away what that figure was. Size, shape [They do have a distinctive silhouette], those unbelievably bright blue eyes, and its voice. Unless people forgot what the White Walkers sounded like, looked like, and forgot they had blue eyes in just nine episodes. However, considering the complexity of the show [due to the original material] I don't blame them for being confused- GRRM is a genius at hiding plot points for whole books if necessary and then unveiling them to a reader's horror. Unfortunately, that doesn't work well with a TV show that also needs to satisfy a casual audience.
Edited by Maester Nikolas, 11 April 2012 - 12:42 PM.