To save you a trip to Wikipedia, Beowulf is an Anglo-Saxon poem about a Norse warrior who fights monsters and becomes king. The game places you in control of Beowulf in a third-person action game where you have to balance his schizophrenic personality: a violent and selfish warrior with a selfless leader.
The classic poem is translated into a traipse through a grim version of Denmark, where you take Beowulf from fighter to ruler. He's a hands-on kind of guy: the game's meaty battles are full of breaking bones and concussive impacts, combos string together ever-more violent moves, where a punch will lead to a twist of a body and a hideously snapped spine.
With the warrior-king in the centre of it, leading his Thanes (soldiers), it's the relationship between man and men that Ubisoft claim will make Beowulf special. You have to make sure your men are suitably motivated, occasionally breaking off from the fight to give them orders via a rhythm action mini-game, egging them on with inspirational chants. As the game progresses you can add and upgrade your followers as well, growing the army that'll support your efforts.
But there's a flipside to Beowulf's character, a rage-induced freak-out that will cause severe damage to any enemies and friends within arm's reach. Injuring your own men too much will naturally damage your relationship with them, ensuring that they won't be there when you need them in the heat of battle.
This sort of vast smash-'em-up works well on consoles, but it's still a niche on the PC. We've not really had a good brainless brawler since The Lord of the Rings: The Return of the King surprised everyone by being genuinely good fun. Beowulf is looking promising, but I'll need a further hands-on to be fully convinced of its merits.