I am continually impressed by OpenAI, whenever we think that something is too difficult for our currently understanding of AI. With their Dota AI and this they have shown that more can be done with a lot less than previously thought.
Of course these works are cited in related works of paper as they should be; perhaps the OpenAI blog should also provide more context on where this stands wrt prior work, as many non-researchers may read this is may be quite misleading...