When Air China's entertainment system suggested this to me, I had no idea of what this was about - but I was immediately captivated, as it looks like a Ghibli movie, only not from Ghibli but from unknown Chinese animators. So I watched it in Chinese (even if I don't understand it) and I liked it so much that as soon as I got home I started to search for the web animation series from which the characters are taken.
The drawing style is deceptively simple, but the backgrounds and scenery in the first half are nothing short of wonderful. They recreate that magical atmosphere of a lost natural world that you may remember from Mononoke Hime or Totoro, with the movie being a bit of both - a peaceful and funny (lots of gags!) growth experience for a young, exhuberant demon-cat-kid, but also the tale of the clash between nature and mankind. (Since young and self-confident China is not old and weary Japan, though, the moral angle on this will end up slightly differently...) But what is really outstanding is the characterization of the protagonist, in terms of story and in terms of animation. It is very well done, and you will really root for Xiaohei as the character grows in several dimensions.
The final part is IMHO a bit less convincing and not so Ghibli-esque, as it focuses on solving the conflict that has been building up throughout the movie, and at times becomes more like a superhero fight sequence. However, in the overall this is a really good animation movie and if a Western edition comes out you should definitely not miss it; in the meantime, you can look for it online, and even the unsubtitled Chinese version will do (there is not a lot of dialogue and you can figure out the story quite easily without it).