Here is the full list of all 10 Galaxia Conquestum achievements.
Destroy 100 ships.
Destroy a super battleship.
Destroy a battleship.
Beat the game on hard difficulty.
Win the game as The F5 Directive.
Win the game as each faction.
Beat the game on normal difficulty.
Win the game as The League.
Beat the game on easy difficulty.
Win the game as The Collective.