I've played it quite a bit. Kind of felt obliged to, since Utopia, the spiritual prequel, was one of my favourite city-building games.

I found K240 to be quite innovative, and simply put, a lot of fun. My copy was a bit bugged, though, and would crash for seemingly no good reason. Hence, I never got that far in the game.

If my memory serves me right, the harder opponents were batshit insane.