As others have stated, the movie usally falls short of the book. But while I had high hopes that this adaptation would be as well done as the first, the many and far-reaching departures from the book's story were almost enough to ruin it completely.
I DID enjoy the movie. I thought it very sad, though, to see how much the story had been "watered down" so as to make the movie less controversial (to Catholics) and less complicated (to those who hadn't read the book - or who don't actually pay attention).
It didn't surprise me at all that Dan Brown wasn't given the screenplay credit.