In my mod I have been developing, although slowly, culture groupings. A culture group is more or less a category which a civilization belongs to. For example, European. While each civilization in the group has unique properties, like buildings and units, overall the playstyle of the group is the same. Playing a European civilization, whether it be Western European, Hellenistic or Eastern European, is going to more or less play similarly to a normal Civ4 experience. I got this idea from Age of Empires 3. Asian civilizations, by contrast would have a slightly different play style. I have not yet decided how as of yet. Asian would mean China, Japan, Khmer, Thailand, Malay etc, so more or less east and southeast asia. India would be its own group, since India is not a civ in my mod but is more historically represented as multiple civs. The fun and challenge of this idea is to come up with how a group is different, and by how much. I thought of Native American civs not having access to horses, but I decided against that. Also thought of different groups having a religious bonus, but that isn't what I'm looking for. The question remains is how groups play different, and this is something civilizations in the group have in common.