Please do not include boob bounce in the final idle stance. If you think about what distance one pixel would be if you sized it up, her boobs would have to bouce around a lot. Subpixel animation could manage that, but I dunno.
:\ I agree with xion, why slam femininity (and sexual, at that) in her face that most normal girl don't even have? Plus, maybe she's a tomboy.
And I like tomboys <3
..
Regarding the desert picture, one more parallax layer with the same one-color style in front of the one that already is there would bring everything together nicely. Or so I think.
Regarding the wings, a series of double-jumps in decreasing strength would rock. Each extra-jump being a wing-flap. And then a power-up or special move that gives all flaps equal strength (with the result that she becomes able to fly :])
... Would be cool. > _>