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With the arrival of CIV, much of what has been true in the world of C3C is gone forever. Many things have been changed, and it's true that some of these things will not please everyone. Overall, though, the game is vastly improved, and its playability for Multiplayer is much better than it was. An honest review of Civ4 Multiplayer by Friedrich Psitalon
Let's start with the bane of C3C: Connectivity and everything surrounding it.
I fully realize that even as I say this, people are going to raise a very high eyebrow, but I'll say it anyhow - you're going to be amazed. Gamespy NAT negotiation allows people behind routers, firewalls, etc, to play with no trouble at all - no opening or closing of ports, zones, etc. If needed, Direct IP still exists, and WOULD require playing with ports, but the only port you need to open is 2056, or whichever port you specify in your INI file. The days of "X can't connect with Y ever for some weird reason" are over.
How does "gone" strike you? If someone has a different version than you (meaning modded files of any type) you'll see the OOS return - otherwise, never again. The game has even shown the ability to "resynch" itself if a genuine problem arises temporarily (hotjoining players sometimes cause a 1 or 2 second OOS.)
Reloads? Oh yeah.. I remember those. The only time you'll be reloading a multiplayer game now is if everyone decides to take a break. Hotjoining allows a player to jump right back into the action if they drop. In the meantime, every other player in the game votes to decide between ...
The Goals file defines the various goals that the AI can pursue. The various goals that are defined within this file can then be set from the Strategies file where they are given priority ratings and other attributes.