The game is fun and enjoyable with friends but it ends there, single player is perhaps the worst experience for a simple reason: The AI cheats.
Yep, full metal cheating, they will spawn armies in areas that you can't see, teleport across the map, spawn in (seven??) Cities in a single turn, build wonders in 2 turns in cities with a single population, they know what you're building where at all times, they'll bomb you with planes then demand the secrets of flight in exchange for peace?? There really is no limits.
So, yeah, it gets a star back for the immensely fun multiplayer but single player is trash, hope you've got some friends.