Symbolism.
Nicely done for a stick flash. Most of these normally suck. However, the scene when the two separate swords clash, you obviously went for some symbolism there. The good guy gets the white background, the bad guy gets the dark background. Though it seemed a little bit too obvious. Try having the bad guy come out from the shadows, and the sun or something being behind the good guy, this way the two contrasting backgrounds have a purpose for being, rather than just a straight up fade.