Pretty funny music, haha.
But yeah, I think I'd agree with Travis; it might be that the movement's not being moved "cleanly" across whole pixels; when the renderer draws the object, it does the best it can with the sprite not "on grid", and might draw it "rounded off" to a position, which is different on the next frame. Another way to fix this might be to move it as you like, but snap the drawn position of the sprite to solid intervals of whole pixel steps.