I don't see why people are hating on this film, I personally love it!
I think the characters are great and the story is very entertaining.
Also to all the people who are saying its bad due to the "inappropriate references" clearly don't understand that some parents have to watch movies with their children, adding humours (adult) references THAT THE KIDS WONT UNDERSTAND, is exactly what makes this film good!! it means not only are the children enjoying it but also the parents made to watch it with their kids they can enjoy it without falling asleep.
One of the best animated films I've seen in a long time!