The Fermi Paradox
In the Fermi Paradox the player decides the fate of all the newborn alien species in a young galaxy. Those civilizations start in the stone age and advance over millennia into a spacefaring society. They will send out radio signals to other planets and before those messages reach other intelligent beings the senders might destroyed themselves via warfare. Spaceships will be send out to explore other stars and the contact between alien races may not always be peaceful.