I really enjoyed the character arch of both po and zhen. It was one of the best I've seen, and the kind that would be expected from a cartoon. Even though the movie lacks the depth with its plot, it didn't matter because I really understood how it is based on the characters and uses the plot to enhance the idea of Po changing from the dragon warrior to the spirit master and to top it of, it uses the plot to also eventually prepare zhen to be Po's successor.