Ignore the stupid picture of Grendel in the promo here, the complaints about "dead" faces and poor effects. Yes, computer imagery gives the faces a static look, but the effect is to make them a bit archetypal, larger-than-life.
Ray Winstone starts out with an egotistical, narcissistic gleam in his eye, but in time takes on the same haunted look as Anthony Hopkins, and by then we know why. Don't see this film for a pure action fix: movement of physical bodies is unrealistic and full of escapist cliches. But this is far less of a distraction than the hyperactive camera work of many recent action movies. If anything, the animation provides a surreal tone that suggests a story as old as the hills - and if Neil Gaiman combines it with another legend entirely, he does so in a tradition that's also as old as the hills.
Purists take note: legends have always been altered and recombined for newer generations and always will be. The old Beowulf version that surfaced in England seems to have been chiefly concerned with providing a role-model for young males: dark-age Beowulf spoke and acted as a man should, and his monster-fights were there to impress the audience so they'd take him seriously and sit through a poem made up 90 per cent of boasting and back-slapping. It was a great poem but needed something more to work visually. This film has that something more, and it does work.