I have playing in Civilization-like game since 1991 year and is mastered in Civ1-2-3, Alpha Centauri, CivCTP. But I don't see the deep multiplayer abilities here.
To say more strictly I even don't see the progress of commercial civ-like games. They are too simplified for feeding the wide masses of consumers, not for hard-core strategic players.
So when in 1999 year I found the PBEM version of Civilization, E-Civ, I was very sceptic. But the time is completely change my mind.
The game have unique economic and military model; one of the most impressive features is the correllation of almost all aspects in the game. You RULE the empire in the world of real players.
I suggest the real strategic players try this beatiful but very hard game.
The E-CIV based standard PBEM principles - client program for viewing the current turn and making orders, and server program for turn processing. So no single play, sorry.
If you are interested, visit the official game site.
Or ask here.