I have a weakness for strong contrast .... I just love those opposing lights and darks so I can't comment much on your values. But I did note a few others things.
1. When a woman lifts her arms her breasts do not remain rounded, the portion under the arm becomes raised.
2. The woman you have depicted is very slender. It would be rare for her to have such an obvious "line" between her buttock and her thigh.
3. Her leg seems disproportionate
4. Her foot appears twisted. When a woman raises he leg behind her it is rare that she would also twist her foot sideways
5. The right side of her dress appears to extend too far out, indicitive that one side of the dress is longer than the other
6. There appears to be something off about this creatures buttocks
7. The enemy is missing anything below the torso - there should be something to reflect his anatomy/size etc.
8. I realize that the woman is very slender but her arms seem remarkably thin, almost too thin. To swing a sword would take muscle regardless of how small those muscles were
9. Her face is slightly skewed
10. "If" she is falling her hair would understandably raise above her ahead - but I get the feeling that she is in mid swing - drawing the sword back with an effort, ready to swing/slash forward - and in doing so her hair would extend directly out to the left of the painting.
I hope these help!
"Creativity emerges only when the imagination is given the freedom it deserves."