This is terrific! Compositionally, it is similar to the Dark Phoenix cover from XMen, when Jean Grey left nothing but bodies in her wake. In this case, Ginny is leaving Harry alive to suffer. She's much more cruel.
This is amazing from so many angles; I love the way you drew the spell, the look on Harry's face, the way Snape looks so broken.
The horror just pours off this picture. Amazing, amazing work.