Background animation is HORRIBLE

I know. That is why I looked up this movie on imdb. I was looking for some kind of explanation as to why the background drawings are of such poor quality. Not just poor but blatantly poor. I only saw a few parts but I saw them go to the Great Wall of China and it was just pathetic. It looked like a half-assed sketch. What little colour there was was all wrong. Was the budget that small they could not afford to complete the backgrounds?