Civilization II ends (for the non-warmongers) with the colonization of a planet in the Alpha Centauri solar system. I remember completing the journey for the first time and being sorely disappointed that I was not able to oversee the colonization of the new world -- instead I got a short cinematic. With the release of Alpha Centauri, civers everywhere finally got the chance to finish the job.
The game is remarkably more complex than its predecessor. Ideological factions take the place of nationality-based civilizations; a myriad of "social engineering" choices are available instead of simplistic governmental options; units are now customizable to an absurd degree; diplomatic tools are more plentiful; the list goes on...
Also superb is the atmosphere generated by the game's numerous snippets of wisdom, cinematics, and back-story. Each new technology and facility acquired is accompanied by a quote from one of several literary works, both real and fictional, or some other appropriate sound byte, usually read convincingly by one of the voice actors who portray the faction leaders.
I can think of only a couple of complaints. The game has a steeper learning curve than do the Civilization games. While this is due in part to the increased complexity of the game, another factor is lack of intuitiveness. With Civilization, it wasn't hard to remember the purpose served by the various units and improvements, because they were all drawn from history. In Alpha Centauri, the game is based in large part on the imagination of its designers, making it more difficult to get the hang of the game's components. But once you play your first several games, you'll be frightened by the number of the game's nuances you are unable to forget.
Another disadvantage of the game's complexity is that the AI isn't particularly adept at finding and exploiting the most powerful strategic configurations. Population Booms, Supply Crawlers, and certain customized units are game-breaking strategies, which are rarely if ever employed by the AI factions and the result is that games are not terribly challenging unless you stack the deck against yourself intentionally. The AI tries to make up for this by being overly aggressive, which detracts from the realism of the game. You have to shake your head when the "Peacekeepers" and "Gaians" (environmentalist faction) start tossing around PlanetBuster ("quasi-nuclear") weapons like cheap firecrackers. However the AI isn't much better at tactical planning than it is at civic planning, so this doesn't increase the difficulty of the game substantially.
This is a very-well-made game that takes a big step towards transforming computer gaming into an art-form. With the retail price of this game down around $15 as of now, you can't go wrong.
