First of all, the colors are great. The setting and concept makes this piece even more amazing, and I absolutely love her outfit. The fact that she has two swords astonish me.. thank you for implementing that detail!
The expression on her face and the way her hair looks is great.. she also looks pale and a little sweaty. Like she's really scared, perhaps? No wonder, seppuku is an ancient, oriental suicide-rite, isn't it?
The painting is great... she seems desperate due to failing in the battlefield, but she doesn't really transmit the will of suicide. Maybe a more frontal point of view would work better, with her showing the stomach, making more obvious her final act.
Great work with the colors and shadings
Woo! Awsome, very awsome. I love the expression upon her face, and the colouring is VERY good. I like her armour too... Her pose, I could never be able to do, and the darkness is great. I like the way you drew her hands... Well done. ^_^