Well, even though the animation needs some work, it wasn't bad. However, you had so many unnecessary movements. Like when he ran towards the enemy. Can't point out where, however, but he runs forever. Which reminds me of monty pythons holy grail, where he attempts to run towards to the castle and he runs and runs, but takes forever to get there.
The attack scences is too drawn out. You don't need to see him move his sword through the body of the other in slow motion. Just show the sword on one side, then a blood effect off the enemy, then after that, a quick switch to the next attack sequence. Like he is mad with rage.
He doesn't look mad right now, he looks.. hell? neo-ish? I must kill you for great justice! Huzzah.
Doesn't work. Also, the fact that you made the story optional instead of blending it with the movie to give it more depth.. it was a bad move, which makes me lower your score even further. A retelling of the previous episode from the view of the brother could've helped.
Also, you could've spent more time to portray the anger of the brother as white eyes and dark colors doesn't make him look angry, not if that is all that you do. You could've made him breathe heavily, shown him grit his teeth.. clutch his fist.. then go berserk. Slizing up everything, making the blood fly around him and finally zoom out, showing a field filled with corpses with him standing in the middle breathing heavily.
I think that would've added to the effect of him being seriously pissed off.
Still, i may not have liked this one, but doesn't mean that i might not like your next one. Good luck with your future animations.