Coming back to this, I've played several games, seemingly doing perfectly fine (or more than fine) as various Civs (Norse, Mongols, Turks etc.) where at some apparently randomly calculated point, I insta-lose the game. There is no warning message, no secession of certain cities, unrest or anything like that. I'm playing as Mongolia, having taken about 9.5% of the world land area, starting to push into Russia, a hair's breadth within the UHV. I take Moskva and suddenly, I lose all my cities, in 1 go and get taken to the defeated screen. How is anybody supposed to enjoy this? Like I said, ZERO warnings or even individual cities going independent, just a sudden 'You are Defeated' out of $%£" nowhere.