You mean empty map as just with my civ without opponents?
Isn't there a way to put some sort of hard limit to AI how many units it can make? Just like national units?
Not that I know of any being accessible now.
And, yes, you can play against Barbs, or even "against animals", in C2C.
While it may sound "stupid" for a "full game" goal, it's actually a fun "game mode" of its own (and it's not exactly hard to "mod" the game to literally stay in Prehistory FOREVER, lol).
Point being that, while the FULL mod is super vast and cool - it's still hardly playable in practical terms due to avalanching turn lag and memory errors, rather sooner than later.
Which is really SAD for such a great mod.
Still, you COULD play something like a one-city game of survival against hordes of Barbarians and Neanderthals - with or without the "tricky" option of "emerging civs", lol.
This is why I so love this mod - it provides much more options game-wise than merely "more techs and more units (and a few concepts)" which it looks like at the surface, indeed.
You could just as well play something as un-Civ as "Pokemon: Catch em all", what with the huge variety of in-game animals, ya know.
Or turn it up a notch and make it "Civilization: Vassalize em all", though that is a bit "boring" for how base-Civ it is, mwahahaha!
The roster of your potential gameplay "goals" here is QUITE wide.