Here's what I have thus far:
Sid Meier's Alpha Centauri
Soon after the 23 hours UED scout ships discovered a new planet in the Alpha Centauri system. Investigating further they made contact with the inhabitants, colonists claiming to come from Earth, calling the planet Chiron or simply "Planet", as well as alien factions they could not understand. They also intended to subjugate the locals and wipe out the aliens, but soon learned of the United Federation of Planets presence in the star system. The UED leaders did not want to provoke war with this powerful faction, and seizing territory in a system claimed by them was considered to be a probable catalyst to such a conflict. So they decided to take a different tactic, establishing an outpost in an a distant corner of the planet, which they would use to keep in contact with the natives. Over time they managed to attain a considerable amount of influence with two factions who had similar ideologies to their own- the militaristic Spartan Federation and the oppressive Human Hive. They intended to use these factions as proxies to conquer the others. However, the Federation also made contact with the natives, seeking to understand the alien factions and built up a relationship with several factions, especially the UN Peacekeepers and the socialist Free Drones, hoping to unify the planet under one government and have it join them.
One of Planet's most notable characteristics is it's native lifeforms, especially the xenofungus and the mind-worms that existed in a symbiotic relationship with it. The mind-worms are protectors of the xenofungus, massing into boils that attempt to viciously attack humans who disturb Planet's ecology (which almost all factions do to an extent, even Gaia Stepdaughters and the Planet Cult are at times attacked). They're physical attacks are vicious, but they are most feared for their ability to psionically assault their foes. These nightmarish visions allow them to overwhelm their prey as they are nearly helpless as the worms burrows into the eye sockets or other holes in the skull and attempt to lay their larva in their brains. Only the most disciplined troops can resist this long enough to strike back at the worms. Some mind-worms form aquatic boils known as Isles of the Deep and others are capable of flight, known as "Locusts of Chiron" However, mind worms have some uses. For one they're husks are extremely valuable, called "planet-pearls" by the colonists. Also some have actually managed to tame the mind-worms, especially those in tune with Planet. This fact has earned Planet some fame in the galactic community and even beyond. Morgan Industries has been attempting to capture them and export them, especially to the UED and Galactic Federation, however their attempts at breeding the creatures in captivity have been stymied by their abuse of Planet’s ecosystem. Furthermore a Zerg scout brood has apparently been attempting to land on the planet, only to have their attempts be intercepted by the UED. However the mind-worms are not even the most spectacular aspect of Planet's ecology.
Planet's life as a whole makes up an entity with some level of intelligence and self awareness. The mats of xenofungus covering the world is essentially it's brain and the mind-worms and some other native lifeforms serving as a sort of immune system. The colonists have also discovered something else. The Planet-mind is "awakening", becoming more aware and intelligent. The various faction leaders and others on the world have even begun to be contacted by what is being called "the Voice". Also they have begun to learn through this contact and contact with the alien Progenitors that this is all leading to something called "the Flowering" the Planetmind will briefly transcend into a state of god-like awareness. Unfortunately these episodes are unstable inevitably leading to a dying out which starts the process all over again. Humanity's prospects of survival if this happens are fairly grim. However some are talking of a possible Transcendence, joining humanity with the Planetmind and allowing the planet's awareness to continue. However this will not happen for a long time yet, centuries in fact. Unless, that is, certain factions succeed in accelerating it.
The two Progenitor factions are locked in a genocidal war, a war that can only end in the annihilation of one side, or the other. The Manifold Caretakers are basically conservative, seeking to prevent anyone with interfering with the Manifold Experiments, of which Planet is one and attempting to prevent the Flowering. The Manifold Usurpers seek Godhood, hoping to exploit the Flowering and Ascend. The alien factions are not particularly friendly with any human faction, seeing them as at best temporary allies, thought the Caretakers are slightly more friendly to those factions who are respectful of Planet and opposed to those who exploit Planet. Even the Federation has been only able to make limited diplomatic progress with either faction. They will become angry with any faction that allies with their enemies. The Progenitors on Planet are just small portions of much larger interstellar empires, cut off from their main forces. The Progenitors originally had a Tech Level of at least TL 9, however over centuries of conflict they lost much of their knowledge but are still approximately TL 8. The Progenitors on Planet have lost even much of that knowledge and are somewhere between TL 6 and 7, though more advanced than the human colonists (who are basically TL 6). The Progenitor core territory is believed to lay on the far side of the Alpha Quadrant.
