The new movie has something of the same relationship to the Anglo-Saxon poem that 300 had to classical history. The title is the same; most of the same characters are present--but let's just say that I would never have imagined Grendel's mother to look like this!
Someone was clearly enamored of how 300, with its digitally created backdrops for live actors looked, and figured, what the heck, we have to create Grendel and other assorted non-existent critters digitally, why not do that with the people, too? My wife's reaction (after she got over the travesty that they made of the plot) was that the effect was too much like Shrek or Toy Story.
The humans were better (technology marches on), but I'm not persuaded that it did anything for the movie. At least Shrek and Toy Story were comedies. This cartoonish effect for what is a combination of a horror story and a morality play just doesn't work.
Another irritant to my wife (whose MA is in English Literature) is that the poem was apparently a pagan folktale that, because of the recent Christianization of the pagans, had been recast into a morality play of good and evil. What few references there are to Christianity in the movie are mild little snipes. But then again, you might argue that there's some merit to it. Beowulf was written on the cusp of the Christianization of pagan Scandinavia; this movie was written on the cusp of the de-Christianization of the West, so perhaps it all kind of fits.
Why did they digitize all the people, and not just the monsters that needed special effects? Because had we seen Angelina Jolie truly as naked in film as she is in digital effects, it would not have been PG-13 (for violence), but R (for violence and frontal female nudity).
I'm a bit disappointed. As an action adventure kind of tale, it wasn't too bad, and some of the special effects are pretty cool. But as my wife observed, on our way home, The Thirteenth Warrior told the story of Beowulf more accurately, and more appropriate to its chronological setting than the movie of Beowulf! And The Thirteenth Warrior was set several centuries later!