"A" for effort, but...
...but somehow the whole movie is dissatisfying. At the risk of running contrary to the popular opinion, I didn't find the humour in this film very funny at all. Actually, everything was awesome, EXCEPT the movie itself. The voices are not memorable, and the jokes lack confidence and feel dated. Although your script seems solid enough, the voice acting is a little off. I would suggest more takes on dialogue and less shooting rodents. But I must say, the artwork is incredible.
And in conclusion, Sub-Zero is a humongous loser.