Sid Meier's Alpha Centauri

Alpha Centauri, a turn-based strategy game with a hard science fiction setting, is played from an isometric perspective. Many game features from Civilization II are present, but renamed or slightly tweaked: players establish bases (Civilization II's cities), build facilities (buildings) and secret projects (Wonders of the World), explore territory, research technology, and conquer other factions (civilizations). In addition to conquering all non-allied factions, players may also win by obtaining votes from three-quarters of the total population (similar to Civilization IV's Diplomatic victory), "cornering the Global Energy Market", completing the Ascent to Transcendence secret project, or for alien factions, constructing six Subspace Generators.

The main map (the upper two-thirds of the screen) is divided into squares, on which players can establish bases, move units and engage in combat. Through terraforming, players may modify the effects of the individual map squares on movement, combat and resources. Resources are used to feed the population, construct units and facilities, and supply energy. Players can allocate energy between research into new technology and energy reserves.

Space-race victories in the Civilization series conclude with a journey to Alpha Centauri. Beginning with that premise the Alpha Centauri narrative starts in the 22nd century, after the 2060 launch of the United Nations colonization mission "Unity" to Alpha Centauri's planet Chiron ("Planet"). Unbeknownst to humans, advanced extraterrestrials ("Progenitors") had been conducting experiments in vast distributed nervous systems, culminating in a planetary biosphere-sized presentient nervous system ("Manifold") on Chiron, leaving behind monoliths and artifacts on Chiron to guide and examine the system's growth. Immediately prior to the start of the game, a reactor malfunction on the Unity spacecraft wakes the crew and colonists early and irreparably severs communications with Earth.

After the captain is assassinated, the most powerful leaders on board build ideological factions with dedicated followers, conflicting agendas for the future of mankind, and "desperately serious" commitments. As the ship breaks up, seven escape pods, each containing a faction, are scattered across Planet.

In 1996, MicroProse released the lauded Civilization II, designed by Brian Reynolds. Spectrum Holobyte who owned MicroProse at the time, opted to consolidate their business under the MicroProse name, moving the company from Maryland to California by the time the game shipped, and laying off several MicroProse employees. Disagreements between the new management and its employees prompted Reynolds, Jeff Briggs, and Sid Meier (designer of the original Civilization) to leave MicroProse and found Firaxis. Although unable to use the same intellectual property as Civilization II, the new company felt that players wanted "a new sweeping epic of a turn-based game". Having just completed a game of human history up to the present, they wanted a fresh topic and chose science fiction.

With no previous experience in science fiction games, the developers believed future history was a fitting first foray. For the elements of exploring and terraforming an alien world, they chose a plausible near future situation of a human mission to colonize the solar system's nearest neighbour and human factions. Reynolds researched science fiction for the game's writing. His inspiration included "classic works of science fiction", including Frank Herbert's The Jesus Incident and Hellstrom's Hive, A Fire Upon the Deep by Vernor Vinge, and The Mote in God's Eye by Larry Niven and Jerry Pournelle for alien races; Kim Stanley Robinson's Red Mars, Slant by Greg Bear, and Stephen R. Donaldson's The Real Story for future technology and science; and Dune by Herbert and Bear's Anvil of Stars for negative interactions between humans.

Alpha Centauri received wide critical acclaim upon its release, with reviewers voicing respect for the game's pedigree, especially that of Reynolds and Meier. The video game review aggregator websites GameRankings and Metacritic, which collect data from numerous review websites, listed scores of 92% and 89%, respectively. The game was favorably compared to Reynold's previous title, Civilization II, and Rawn Shah of IT World Canada praised the expansion for a "believable" plot. However, despite its critical reception, it sold the fewest copies of all the games in the Civilization series.

It sold more than 100,000 copies in its first two months of release. This was followed by 50,000 copies in April, May and June. In the United States, Alpha Centauri was the tenth-best-selling computer game of 1999's first half. Its sales in that country alone reached 224,939 copies by the end of 1999, and rose to 281,115 units by September 2000.

There have been no direct sequels beyond Alien Crossfire, something that writer Greg Tito attributed to Reynolds leaving Firaxis in 2000 to form Big Huge Games. Alien Crossfire producer and lead designer Timothy Train also left Firaxis with Reynolds. However, a spiritual sequel, Civilization: Beyond Earth, was announced by Firaxis in April 2014 and released on October 24, 2014; several of those that worked on Alpha Centauri helped to develop the new title. A review in Polygon noted however that while the new game has better graphics, its story fails to rival the original, a sentiment echoed by another review in PC Gamer. Another in Engadget noted "as a spiritual successor to Sid Meier's Alpha Centauri, however, it's a cut-rate disappointment".

Many of the features introduced in Alpha Centauri were carried over into subsequent Civilization titles; upon its release, Civilization III was compared negatively to Alpha Centauri, whose Civilization characteristics were reminiscent of faction bonuses and penalties. The government system in Civilization IV closely resembles Alpha Centauri's, and Civilization V includes a new victory condition: the completion of the 'Utopia project', which is reminiscent of the Ascent to Transcendence secret project.