***POSSIBLE SPOILER ALERT***
They will teach you in any basic screenwriting class (of which I have taken) that the key to any good film rests in characterization. You have to create some sort of character sympathy in order to engage audiences. I felt as though unless you read the book, and already had sympathy for the characters, you were left hanging. Bella's character was cold and unappealing, which I would have excused had a cared for Edward Cullen in the slightest. His characterization was rushed, as was the love affair between the two. And, I'm sorry, but in a movie about vampires, a love story won't carry the entire film. There needed to be more drama. One fight scene is not enough. Tension usually is a thread used to hold a film together, here it was a dangling line to which the movie was barely holding on.
I wanted to know more about the family. Kellen Lutz and Peter Facinelli anchored a well cast Cullen clan, but they were underused. The film tried also to establish relationships between Bella and the Fork's High School clan, but besides some scenes invented to instigate some awkward teenage sympathy, they became more of a nuisance than an aid to the plot.
I am glad that the film has found a niche in the teen audience. Not since the late 90's, early 2000's has there been a truly successful love story aimed at that market (think back to the good ole days: "10 Things I Hate About You", "She's All That", "Cruel Intentions".)
A guest on "Table Talk" attempted to compare "Twilight" with the "Harry Potter" series. She thought that "Twilight" would find as much, or more, success. The problem is that with the "Harry Potter" franchise, people who weren't fans of the book, or who didn't read it, can still enjoy the films. With "Twilight" I fear that non-book fans won't find the film nearly as amusing. The good news is that if the creators decide to make the second and third novels into motion pictures, then they'll have two other chances to get it right.