This is an interesting documentary because it represents the official Chinese government view of history. If you want to understand a nation, you have to understand how they see their history and the history of the world.
Chinese history is full of what you could call cyclical disruptions. Throughout China's history dynasties would rise, prosper, then fall amidst revolts, nomadic invasions from the north, economic problems, etc. Each of these disruptions left its mark on China (hell, most of the things that the West and even many Chinese think of as "timeless Chinese traditions" really only became common in the time of Kangzi and Qianlong) but none of them ever shook China's position as the Middle Kingdom. None of them ever really challenged the Confucian worldview either. China's frequent nomadic invaders from the north almost always recognized the downright superiority of Chinese culture and tried to make elements of it their own.
But, watching the video,they totally gloss over the first couple thousand years of Chinese history. I know that's not the topic, but it made me think of something that occurred to me not too long ago in a history of Imperial China class I was taking. China weathered many thousands of years of divisions and invasions but none of them ever presented a challenge like that of contact with the imperialist West. Western culture was totally alien to what China had experienced before. Industrialization meant that the West's military and economic dominance over China was total. That was something China had never experienced before. A foreign power who was totally alien and totally superior. The notions of China as the Middle Kingdom and of Confucian civic and social values as being the method of running a society were shaken to the core. That's why the period of weakness before the West sticks out in China's view of its history (aside from the fact that it's the most recent). Previous problems with foreign powers had never so throughly challenged China's view of itself. Or at least that's my theory.