There are a handful of co-op scenarios, one involving winning by trading. The "skirmish"-style games can be set to have either "allies", where you operate separ

There are a handful of co-op scenarios, one involving winning by trading. The "skirmish"-style games can be set to have either "allies", where you operate separate economies but are on the same side, or "shared kingdoms" where you share everything except your starting locations. Shared Kingdoms is lots of fun!