Does that mean if the program read additional texts on Civilization strategy that it would get even better? How about texts that may be somewhat related but not specific to the game (combat strategy, world history?!...)
From the looks of it, the program merely learned the rules of the game by doing textual analysis of the manual, and maybe got a few strategic hints as well. As for actually learning to play the game _well_, my sense from the article is that the program then used more conventional machine learning techniques to test and adopt winning moves.