Look, I know the drill. If any element of the Twilight movie varies even slightly from the way you pictured it in your head, then it is the worst film ever made and you hate it and Catherine Hardwicke has ruined your childhood. Or, alternatively, you've built up so much anticipation for the movie that you're going to love love LOVE it no matter what, even if it's bad, you don't care, you refuse to listen to any criticisms LA LA LA I CAN'T HEAR YOU. I know how it goes.
The book's most devoted fans are seeing the film anyway, so I guess I'm talking to everyone else -- those who haven't read the book, or who (like me) read it, mostly enjoyed it, then didn't give it another thought. Is the Twilight movie of any use to those people? Or, as a friend asked me, does it work purely as a vampire movie?
Oh, heavens, no. Noooooo. This is not a vampire movie. This is a somber teen romance that happens to have some vampires in it. Little attempt is made to establish the mythology of the bloodsuckers, and the supernatural elements are downplayed -- a wise move, since the special effects, when they are necessary, are at about the level you'd expect from a movie that is more focused on romance than sci-fi action.
All of which is in keeping with the tone of Stephenie Meyer's book, which is eight parts romance and two parts action/fantasy. That's why it's been such a phenomenal success with women, and why the male-dominated geek industry -- the Nerderati, if you will -- has been so skeptical of that success. "What?" they scoff. "A super-popular vampire book that we, as men, AREN'T interested in? Inconceivable! It must be terrible, and its popularity is probably being over-reported!"