As far as mechanics go I think that shifting the torso by a pixel on impact might sell the force more. Exaggeration is key, but can't be overdone... so I could be wrong on that one, it looks balanced/martial enough.
A smear or motion blur effect on the blade could work too if that's something that fits in the game's style.
Otherwise there's also some jumpiness in the anim that you could iron out, or make the implied transitions between frames smoother, by tweaking subpixels to make it flow better. (I.E. legs.)
I know these concepts are hard to explain in the span of a short post or by text alone so I'll probably be making a small edit soon and putting it here.
(BTW apologies for the stub posts recently, life has been busy in general.)