Beowulf, the text, is all about contrasting imagery: light and dark, good and evil, pagan and Christian. The imagery from the text associates all dark imagery with evil and light imagery with good. The movie, the 2007 production, seems to flip this imagery. In the movie, Grendel's mother (played by Angelina Jolie) is depicted as a golden woman; therefore, in accordance to the text, this would align her with light and good. There are also references to Beowulf as being dark- a complete contrast to his characterization in the original text. Also, in the movie, Beowulf is not seen as the typical Epic Hero. He fails to adhere to the characteristics of the Epic Hero in the movie and, again, this would pair him with being evil. The text supports Beowulf as the perfect warrior; the movie shows him to possess major character flaws.
Also, the text seems to be a call to Christianity. Which, again, would align the text with "good"- depending on one's views. In the movie, Hrothgar refuses to pray to the Christian's God. This is simply another example of how the movie twists the imagery and thought behind what is considered good and what is considered evil (in regards to the text's point-of-view).