I'm old enough to have played Civ I when I was a child, but have not played since then. So, why didn't this project choose to create a Civ 7 or Civ 6 play-alike, nor a Civ 1 play-alike, but rather Civ 3? What's special about it?

More generally - if someone remind us of the major differences between the different versions of Civilization, in a nutshell, we would be in your debt.