I understand why some filmmakers make changes when they make a movie out of a novel. The two art forms are different. The movie version of Voyage of the Dawn Treader added some plot elements–the green mist, the seven swords–but, as my wife said, they sort of served the larger story, tying together an episodic plot that works better in print than on the screen. The movie nailed the characters, though, especially Lucy, along with a Reepicheep wonderfully voiced by Simon Pegg.
The Christian elements were there, with lots of talk and examples about not giving in to temptation, something you don't hear about in most movies. In the book, Aslan scratched out Eustace's dragon-nature, supplemented with some great baptismal imagery. In the movie, once Eustace turns into a dragon, he does all kinds of heroic deeds, and then Aslan changes him back (without touching him, though). One could construe that as implying that a person does good works, which then merit God's grace. Whereas the book has the grace coming first, and then the good works. But I think the theology was unintentional. In a movie, if you go to the trouble of devising a good special effects dragon, you need to have it do as much as possible. The movie did include one of the Narnia series' most important lines from Aslan, where he tells the children that when they go back to our world they will have to know him by a different name, and that the reason he brought them into Narnia was so that they could know him better in their world.
So I thought the movie was good. I enjoyed it. I recommend it.
And yet why do I feel so lukewarm about it? I realize that a novel has characters, setting, plot, and theme. The movie did an OK job of approximating those. But a novel also has language. It also conveys a feeling. I guess it was the feeling of the Narnia books that I was missing.
Because the story in a novel is happening in your mind, as you picture the events in your imagination, the effect is deeper and, by definition, more imaginative, than just watching images on a screen. Reading entails an inner experience. In movies, we are more detached from the images we are watching.
There is another problem, though. Movies today have a hard time rendering fantasy. Yes, they can now create the most fantastical special effects. But because they are so realistic, so hard-edged, the elements that make fantasy–namely, mystery and wonder–are dispelled. Fantasy needs to have softer edges to work. I had the same problem with Inception, an interesting movie about the relationship between dreams and reality, but there was nothing dreamlike about any of the dreams! Movies and special effects today are just too literal! (Come to think of it, I recall Lewis making this same point, about how fantasy doesn't work well on the stage or in film. Does anybody have that reference?)
I do think a movie maker will one day figure out how to use special effects to create truly special effects in the imagination of the viewers.
I can think of one example, though, of a fantasy movie based on a novel that worked in its own terms and in capturing the feel and the imaginative rush of the original. That would be the Lord of the Rings.
Why do you think the movie version of Tolkien's trilogy worked so much better than any of the movies of the Narnia series?