This post was published more than a few years ago (on 2004-02-20) and may contain inaccurate technical information, outmoded thoughts, or cringe takes. Proceed at your own risk.
I haven’t read the book, but my wife tells me that the first two acts of this film (the ones I call “maddeningly intriguing”) are the closest to the source. It all comes together in the end, but the re-emergence of Finn’s benefactor took the film on a seemingly unnecessary action-adventure bent.