I'd like an answer to this, also. I started my first campaign on normal, just to get the feel of the game, and have been using very hard since then. I can't see any real difference. I had just as many rebels, and my cities were just as filthy on normal as very hard. I don't autoresolve, so not sure about that one. Would figure it would be more difficult. The "logic" of the AI doesn't seem much different, and that's where it would be important. Still pretty lame. Still attack with small stacks, seldom blockade ports, seldom attack my ships if in port, etc. There has to be some tangible difference. I haven't even noticed a significant difference in vices and virtues (whatever). By now, someone has to have figured this out.