Enemy Unknown — Ufo:

Interrogating high-ranking alien captives reveals that the various species are being manipulated by a master race. The Revelation

If X-COM goes bankrupt, loses all its bases, or fails the Mars mission, the Council of Funding Nations surrenders. In the PlayStation version's defeat cutscene, the aliens violently murder the negotiator sent to discuss terms. Legacy and Continuity UFO: Enemy Unknown

Destroying the Alien Brain severs the link between the invaders and their leadership, causing the alien forces on Earth to collapse and saving humanity. loses all its bases