My guess is it's the rippling muscles of Jacob Black (Taylor Lautner) that have all the girls heating up.
The acting is so one-dimensional and the plot so loosely based on legend - you'll find followers of the vampire tradition extremely outraged at the fact that vampires in this series sparkle in the sunlight rather than poof into a pile of ash.
Don't get me wrong, I'm a fan of the books - but more especially of Jacob's rippling muscles. My guess is that with the Twilight series, it's pure, simplistic escapism - nothing more and nothing less. There's not much thought-processing involved and that's what's captivated audiences in today's world full of deep, insightful questions.
The introduction of the wolf pack is a big draw-card for this movie as the love triangle between Bella, Edward and Jacob deepens. It's not as disjointed as Twilight and will certainly have you hooked from beginning till end - including those with low attention spans (myself included). There are moments of cheesiness - chuckles from movie patrons will mark these occasions.
There were two things I noted though while waiting for the movie to start. One was the number of boyfriends who were suckered into watching New Moon - let's face it, this one's definitely a full-on chick-flick. Two is a disturbing one; considering the average Twilight fan is under 18 (I was seated next to a 10 - 11 year-old) showing an advert for Bells Whisky was rather inappropriate, irrespective of whether you have the 'Not for sale to persons under the age of 18; drink responsibly' schpiel. Somebody needs to re-think their marketing strategy.
