Her hair and cape shouldn't be hanging down (since her gravity is reversed), but the picture is otherwise very clever.

The apple falling down into the rising balloon (along with the bite that apparently fell out of Kat's open mouth).

Her hair and cape always follow normal gravity - for example, if she's standing on the side of a building her hair will still fall down toward what we consider the ground.

Also, I really dig this picture! Love the intensity of that blue sky.