While The Lovely Bones is told from a deceased person's point of view, it is not a fantasy. The film version devotes so much time to the fantastical elements of Susie's time in Heaven, that much of the gritty reality of a family's coping with the brutal murder of their daughter/sister is somewhat lost. I think that much of the fantasy feel of the movie came from Peter Jackson who also directed/produced The Lord of the Rings film trilogy. The problem is that Sebold's novel focuses most on the harsh splintering of the Salmon family because of Susie's death--not on Susie's posthumous fantasy world. Much of what makes the novel such a popular read is Sebold's portrayal of reality; in fact, if someone first reads Sebold's memoir Lucky which chronicles her being raped and coping with the aftermath, much of The Lovely Bones becomes even more real to the reader.
So, while critics of film versions of popular books often cite characterization or event discrepancies as reasons for not appreciating the movie version, The Lovely Bones is different in that the filmmaker actually changes the book's focus and tone which to me is a more significant alteration than leaving a couple events out here and there.
In my opinion, one of the greatest discrepancies between the novel and the movie is the manner in which each portrays Susie's heaven. The movie included many scenes that were not included in the novel, especially those showing mystical and strange parts of heaven. These scenes were frequent and lengthy and I did not feel that they added to the power of the story; these scenes actually conflicted with my perception of what Susie's heaven would have been. A more accurate portrayal of Sebold's book would have, in my opinion, been even more moving and meaningful than that movie version.