unfortunately i'm not much of a platformer person, so i can't give any rating on the levels. and also, it wasn't too immediately clear to me i had to DOUBLE PRESS the up button to fly. i think the name should have been "when pigs fly", because at first i didn't see what was role-reversing about this beside the pig getting the butcher, until i saw your reasoning on this page.
it was very polished though, and i think if i were into platformers more i would have enjoyed this.