60		Great Nations (Windows, 1997)
53		Sid Meier's Civilization (DOS, 1991)
51		Anacreon: Imperial Conquest in the Far Future (Windows, 2004)
50		Reach for the Stars: The Conquest of the Galaxy (DOS, 1988)
50		Anacreon: Reconstruction 4021 (DOS, 1987)
50		Spaceward Ho! (DOS, 1992)
50		Imperium Galactica (DOS, 1994)
50		Stars in Shadow (Windows, 2017)
50		Stars! (Windows, 1996)
50		StarDrive II (Windows, 2015)
50		Emperor of the Fading Suns (Windows, 1996)
50		Space Empires III (Windows, 1997)
50		Space Empires IV (Windows, 2000)
50		Master of Orion 3 (Windows, 2003)
41		Master of Magic (DOS, 1994)
40		Sovereignty: Crown of Kings (Windows, 2017)
40		Worlds at War: Conflict in the Cosmos (DOS, 1991)
40		Master of Magic (Windows, 1997)
40		FreeCol (Windows, 2003)

Notes: Games similar to Invasion, Games like Invasion, Windows, Strategy, Tactics, 4X, Turn-based, Top-down, PC, Game Similarities.