You asked for animation critique, so...
I kind of noticed that the characters make big mouth movements all the time. I understand that their mouths should be very expressive, but they kept opening their mouths ALL THE WAY for even the minimal movement. You need to have times where the characters have a smaller range of opening/closing their mouths to contrast with the times they NEED to have their mouths open really wide to be expressive.
I hope that makes sense.
(BTW, the 9/10 rating isn't because of this. I just don't like handing-out 10's)