X-COM: Apocalypse

Story

Half a century after the end of the second X-COM campaign, the final battle of T'leth has severely damaged the Earth's biosphere. As a result, several self-contained megalopolis-type cities were proposed to serve as a habitat for humanity. The game follows Mega-Primus, the first of these cities, built on the ruins of Toronto, Canada. Meanwhile, the off-world colony of Mars is being exploited by the Elerium mining corporation Solmine and suppressed by MarSec (MAR's SECurity). The alien threat in the game is represented by a new race of organic, extradimensional aliens that initially appear to have no connection to the aliens of the previous two games. These new aliens attack the city through tetrahedral teleport gates. The player must figure out how to send his or her own plane, along with X-COM agents, through these gates without being destroyed and take the war to the aliens. There are 14 races of alien beings in Apocalypse, including Anthropods, Brainsuckers, Hyperworms, Megaspawns and Micronoids. Each race has different strengths and weaknesses, and some races are dependent on other races. The "alien life cycle" plays a crucial role in the game. The player learns about this "alien life cycle" through research and especially through the low-level attacks of the aliens when collecting specimens. Most notably, the attacks of the armed aliens, the brain-suckers, who attack individuals after they land from a pod launcher used by alien foot soldiers. The brain sucker hatches and attacks the nearest individual by jumping on their head and seemingly injecting something through their mouth, causing them to die instantly. The life cycle later takes a mysterious turn as it shows no connection between the lower alien forms and the higher alien forms. Eventually, it is revealed that the leaders of the invasion are the Micronoids, a race of intelligent single-celled organisms that live in the bloodstreams of the other aliens. The ultimate goal of the invasion is to inject micronoids into the bloodstreams of important personalities so that they can control Mega-Primus through psionic domination of their hosts. The player's ultimate task is to infiltrate the aliens' homeworld and destroy their side of the gate, as this is the only way to stop the Micronoids invasion.