As you approach the late game, your focus should shift towards achieving your chosen victory condition. Each Affinity has a unique victory, in addition to the universal Domination and Contact victories. The Purity victory involves building the 'Exodus Gate' and bringing colonists from Earth. The Harmony victory requires you to awaken the 'Mind Flower' and achieve symbiosis with the alien planet. The Supremacy victory involves building the 'Emancipation Gate' and sending a fleet to conquer Earth. The Domination victory is achieved by conquering all rival Sponsors' capitals. The Contact victory requires you to build the 'Beacon' and establish communication with an ancient alien civilization. Focus your research, production, and diplomatic efforts on fulfilling the requirements of your chosen victory. This often involves constructing a massive Wonder and defending it from rival Sponsors.
