Whoa, I certainly was not expecting this. You did a really great job here. Your physics and fullbody animation are incredibly impressive and set a new landmark. Sounds/graphics/etc are mostly the same as they've always been, though I like how you made a new twist incorporating the smartphone. Did you animate that on its own and have to pantomime your fingers over it?
There were a few shortcomings I noticed in this animation, or at least things I didn't like, but none of them really takes away from it enough for me to say that this isn't better than the last installment. First of all, your particle effects are not nearly as prevalent in this as they were in AvA3. Second, I felt the story was a little more Disney-esque with the "we're friends now" ending, which seemed a little cheesy to me, given the way the rest of the series has gone. That said, you did a really amazing job here and you really stepped up your game.