Honestly, I know deviation from a book is to be expected, and that's mostly fine. However, I think the deviation from the book for the Red Wedding detracted from it a lot, and I don't really mean the events themselves: the tone of the red wedding was just not as good in the series. What I mean is this: both the book and the series went for "shock value." The thing is that the book's shock value was that it was so sudden. The series went for the "gore" shock value, which just isn't as good. In the book there was virtually no indication of what was about to happen until it happened - I didn't even realize what was happening until the next paragraph! But in the series they lock the doors and give a creepy ominous speech about a 'wedding gift.' And then the coreography of the whole 'slaughter' was so slow and unnatural. But, anyway... effective.