The main gallery is for finished work. Sharing your work there and in the WIP forum sends a mixed message. Post here first, then submit to the gallery once you're all done.

Swinging the sword around like that would probably slow them down and unbalance them, I think you should keep the sword movement much smaller.
Because the sword hides the far arm, because we never see the far elbow behind the body, and because we only see the arm when it's in the front and not in motion, it looks like the far arm doesn't move, even though it does.

Frames 3 and 4 have the near leg in nearly identical positions, ditto for frames 5 and 6 and the far leg. This creates the choppy look, especially the near leg, which snaps to being in the forward position after being still for two frames.

The animation could use some secondary motion to help make it even smoother. Let the scabbard bounce (have the motion drag behind the character's up/down motion), and have the headband flap in the wind. There's already some motion in the headband, but it's very minor. Give it some weight, have it fall down more. Even if it's not realistic, I think it'll look better.

I suggest removing sword completely, leaving it only for attack animation, because ninja is a stealthy character, so running with sword all the time would make him/her more noticeable and less mobile. Also, running animation doesn't underline stealth either, it is more like he is charging into attack. Google "ninja running gif". Other animation problems:
1. legs are blurring together, especially at the back.
2. hands don't really balance the body, and one hand is rigidly static.

Still it is very good for a first animation.


I guess he/she finished it, but also wants some feedback, so he could improve his skill with other works.