Here is the full list of all 21 Power Vacuum achievements.
Win a non-tutorial game.
Finish a game owning most of the colonies (at least 3).
Win a game owning most of the colonies (at least 3).
Finish a game with 3 battle wins.
Win a game with 3 battle wins.
Win a game by capturing colonies significantly bigger than yours.
Add a fully connected Magnum Opus.
Add two fully connected Magnum Opuses in a single colony.
Finish a game with at least 3 fully connected Magnum Opuses, one in each colony.
Play against a bot on very hard mode and win.
Play against 3 bots on very hard mode and win.
Own a colony with 2 vassals.
Own a colony with 3 vassals.
Own a colony with 4 vassals.
Recover from a bad financial situation.
Recover from a bad financial situation and win the game.
Win a game with a single colony.
Achieve $50B in net revenue.
Unlock 3 achievements during a single game.
Unlock 4 achievements during a single game.
Unlock 5 achievements during a single game.