It's hard to pinpoint why this game hits the neurons in just the right way. The voice-acting is superb and pervasive. Every time you build a facility or complete a Secret Project, you hear a character saying something. The sheer amount of text written for this game is only dwarfed by how, for lack of a better word, good it is.
But ultimately, the genius of the game is how it flawlessly blends its great writing with strategy elements. No matter which faction you pick, you are beset on all sides by a pink "Xenofungus," which grows on Planet's surface. The fungus is an important strategic element, as it is difficult to cross and units enveloped within it are invisible to enemies. Xenofungus is not desirable to build bases near, as it cannot be worked to produce minerals or nutrients. It can also spawn nasty critters called "Mind Worms," which attack your bases and units with devastating neural attacks. Mind Worms are somewhat analogous to the barbarian hordes in Civ games but in their familiarity lurks a surprise.
At first, the attacks seem random, but the player, told through text popups, begins to hear strange mutterings from a Voice. The Voice threatens more attacks if the pollution and corruption caused by humans goes unchecked. The Voice, fungus and Mind Worms play out as huge parts of the endgame - I won't reveal how - and the player considers their connections because it's a great story, and if you don't, you'll probably lose.
Alpha Centauri does everything right. Even PC Gamer recognized its greatness, giving the game a 98% score, tied only with Half-Life as the highest rated game in the magazine's history. SMAC won many game of the year awards in 1999. And yet, it has sold the least copies out of all the games in the Civilization series, and receives the least attention. It is not on anyone's top 100 list, and there are not three sequels.
Firaxis designers know it is good. Features first introduced in Alpha Centauri have trickled down into the company's titles. Each civilization's characteristics in Civ 3 is reminiscent of faction bonus and penalties. The government system in Civ 4 is nearly identical to Alpha Centauri, with five different sliders focusing on different aspects of government, like labor and economy.
Why hasn't Firaxis cashed in on what could be a great franchise? Is it because Brian Reynolds left Firaxis in 2000, forming Big Huge Games? Did he take the IP of Alpha Centauri with him or does Firaxis feel they can't make a sequel without Reynolds being involved? Or am I just making all this up and it's the poor sales that have discouraged a sequel? Sadly, neither Sid Meier nor Brian Reynolds is talking.
Whatever the reason, I think they are missing something. The game is still addictive in 2005. Given an entire month to write a great drama, I spent my time instead building needlejets and arguing with Professor Zakharov on where to coordinate our attack plans to wipe out the Human Hive. Creating a future history in Alpha Centauri was more satisfying than writing my own.