Beowulf is an epic hero, who goes and destroys not only the epitome of eveil, but evil's mom as well. And a dragon!
Grendel is one cool monster, who can kill 30 men in one go. And he just attakes at will. A super-evil dude. Causes mass destruction, my kinda bad-guy.
Grendels' mommy is really mean, coming to avenger her son that Beowulf destroyed. How they can fight and live underwater and not die from lack of oxygen, I have no idea. But it makes Beowulf look cool, and then the monsters look evil-er, that they can live underwater and all.
The dragon is awesome, simply because it's a dragon. AND it stops Beowulf. This evil monster and his mom can't, but this dragon can? Sure sounds like this dragon kicks butt. Sure Beowulf is old and all, but still.
Beowulf brags alot, though. That is, however, how the story shows his bravery and past wins. Still seems like he's bragging a lot. He tells Unferth, look what I did, this is why I lost, I could have won easily, but I wanted it to seem fair, and then I killed all these monsters on top of it, even though I lost, but I could have won had I tried.
The actual fighting isn't described in super detail, which is disappointing, yet we konw what's going on and can imagine it all from the story itself. It would be nice, however, to know exaclty what they were doing and how they were hurting each other and trying to kill the other one and all the gory details.
Overall, the story if Beowulf beatin' up on a bunch of monsters, cutting heads off, and then dying. Which is great, because I think that epics have to be gruesome and difficult for it to qualify as an epic. Look at Lord of the Rings. You see how much killing they do in those movies (and the books!), all the destruction, all the evil. Then kicking evil's butt. That's what makes this an epic - Beowulf comes, he sees his enemy, and kills him. Sure he dies at the end, but he has to be almost 70 when he does. And for a person who is killing monsters for sport, that's a long time to live.