I've only scratched the surface of this game.   There are some game design issues which I think are going to be swiftly worked out, so I am not too concerned with that.
 
This might be the fix I've needed for a while.  I turned off my computer at midnight, which is about an hour and a half later than normal.
 
Technical fixes: After updating my drivers, the flickering of the character portraits and cities went away.

I've only scratched the surface of this game.   There are some game design issues which I think are going to be swiftly worked out, so I am not too concerned with that.
 
This might be the fix I've needed for a while.  I turned off my computer at midnight, which is about an hour and a half later than normal.
 
Technical fixes: After updating my drivers, the flickering of the character portraits and cities went away.

I hope you don't get major slow down in the middle or later part of your games as that seems to be a major issue now.
 
My game just started crashing so I'm done with this game for now.