I think this had a pretty good premise. What I really liked about it was how you used the perspective flip. I do wonder why these birds are attacking those pigs. Well, there is a REALLY popular trailer that describes it, but this works well too. I think the artwork is good. The original characters in the game aren't that well detailed.
The sounds are pretty good. I like how crazy the birds sound. That one level I can't beat is the eighth one. I think catapult games are quite cool, especially ones that mix it up like this. At least I got past the first seven leves.