Here is the full list of all 29 After the Empire achievements.
Win the game on The Heir of Destiny (Easy) difficulty.
Win the game on a Small map.
Conquer your first couple hundred million stars.
Win the game leading a Faction with these qualities: Machists, The Righteous Call, Militarized and Serene.
Win the game leading a Faction with these qualities: High Machists, The Higher Path, Gentle and Majestic.
Win the game leading a Faction with these qualities: Transitory Machists, The Veiled City, Mighty and Wasteful.
Win the game leading a Faction with these qualities: Universal Machists, The Infinite Reach, Profiteering and Corrupt.
Win the game leading a Faction with these qualities: Ecstatics, The Joyous Hearth, Hedonistic and Content.
Win the game leading a Faction with these qualities: Greenseers, The Unbroken Word, Absolutist and Efficient.
Win the game leading a Faction with these qualities: Redemptionists, The Common Union, Faithful and Fragile.
Win the game leading a Faction with these qualities: Bearers, The Commerce Federation, Placid and Industrious.
Win the game leading a Faction with these qualities: Epicenians, The Old Kingdom, Poised and Egalitarian.
Win the game leading a Faction with these qualities: Rejectants, The Winding Stair, Pilgrim and Mighty.
Win the game leading a Faction with these qualities: Enigmatics, The Secret Door, Cryptic and Petty.
Win the game leading a Faction with these qualities: Esoteric Enigmatics, The Hidden Hand, Vain and Securitized.
Win the game leading a Faction with these qualities: Reformed Enigmatics, The Golden Shield, Industrial and Poised.
Win the game leading a Faction with these qualities: Categorants, The Martial Heart, Slothful and Militant.
Win the game leading a Faction with these qualities: Nihilists, The Free Republic, Numb and Mercantile.
Win the game leading a Faction with these qualities: Devourers, The Central Authority, Securitized and Hateful.
Win the game leading a Faction with these qualities: Calculists, The Exploratory Society, Egalitarian and Faithful.
Win the game leading a Faction with these qualities: Agnosts, The University Beyond, Glorious and Placid.
Win the game on The Last Old Mind (Normal) difficulty.
Win the game on The Will to Control (Hard) difficulty.
Win the game on The Will to Create (Expert) difficulty.
Win the game on The Will to Conquer (Master) difficulty.
Win the game on a Normal map.
Win the game on a Large map.
Win the game on a Huge map.
Win the game on an Immense map.