This was pretty nice
The art was pretty good, this being your first flash. Nothing moved awkwardly. Sound effects might be helpful, but you still had them timed to the music, which is what you wanted. I just didn't like the volume and the inconsistency of it. The music is all right, but "koto" seems old to me already, especially with the "under the sun" remix used for wii commercials and such. The only thing I can mention in terms of art (because I liked the coloring of this, actually) was how the samurai's gi becomes reversed in the end. It had an interesting story, but without any form of dialog, it confuses me as to why a ninja would attack a samurai. Great job, and I'd sure hope to see a sequel, because your animation can only get better from here.