Forest-sassin Um..
The obvious thing to say would be "It's too short", it is obviously too short. Saying it's too short would help you in no way, so I'll state something different.
I couldn't see it far away, but when I read that it may be a good idea to zoom in, I noticed you had the colored Backgrounds of your sprites still intact in the corners. You need to delete every one of these, it is the most unprofessional thing you can do with a sprite animation.
The bottom line is that this flash is bad. The main problem is that the sprites are so shaky and badly animated. You need to zoom in 2000% and use the arrows to line them up perfectly every single time. You may or may not know this already.
But a good thing you have going or you with this animation, is the genius use of sprites. I noticed at the end Naruto had thrown a kunai upward as if uppercutting and a kunai stuck into the assailant's stomach. Most people just see Naruto's kunai throwing sprite and a kunai next to it and just add the 2 together. The same with punching, kicking and other attacks. You seem to understand not to be bounded by the spritesheet and do very original things with your animations.
But with that said it's not fair to give you anything more but a 4 as it would be unfair to the rest of the sprite animators who painstakingly zoom in every single frame until it's just right.
So in conclusion;
Horrible Animation
Background visible
Genius use of sprites
The Wrong Game 