Galactic Civilizations II: Dread Lords2006

Galactic Civilizations II (GalCiv II) is a 4X Grand strategy game set in the 23rd century, when multiple alien civilizations scramble to conquer the galaxy, planet by planet, by force, diplomacy, influence (culture), or technology. GalCiv II focuses on the single player experience that consists of a Campaign mode and a "Sandbox" mode, and omits multi-player. The game is notable for its artificial intelligence, which is challenging without being given resources and abilities not available to the player, as is common in the majority of strategy games.