Here is the full list of all 47 Supreme Commander 2 achievements.
Win a skirmish match against all AI opponents
Complete all three campaigns 'Normal' difficulty
Complete all three campaigns on 'Easy' difficulty
Complete the 'The Final Countdown' operation
Complete the 'Surface Tension' operation
Complete the 'Gatekeeper' operation
Complete the 'The Great Leap Forward' operation
Complete the 'The Trouble With Technology' operation
Complete the 'Fact Finder' operation
Complete the 'Prime Time' operation
Complete the 'Cliff Diving' operation
Complete the 'Steamed' operation
Get a complete campaign score over 150,000
Complete the 'Back on the Chain Gang' operation
Complete the 'Lethal Weapons' operation
Complete the 'Delta Force' operation
Improve your score on any operation
Complete the 'End of an Alliance' operation
Complete the 'Factions or Family Plan' operation
Complete the 'Titans of Industry' operation
Complete the 'Strike While Cold' operation
Complete the 'Off Base' operation
Complete the 'Prime Target' operation
Win 10 co-op matches vs AI
Win a skirmish match without building any Experimentals
Win a skirmish match with each faction
Win a co-op match vs AI
Win an online match
Win a skirmish match against any AI opponent
Complete both parts of the tutorial
Complete 'Prime Time' with an army made up entirely of Assault Bots
Play 25 skirmish matches with one faction
Complete all hidden campaign objectives
Play 10 skirmish matches with one faction
Complete all primary and secondary campaign objectives
Extract 1,000,000 mass
Build 10,000 units
Win a Ranked online match
Win a skirmish match in less than five minutes
Destroy 10,000 units
Win a skirmish match on every multiplayer map
Win 25 Ranked online matches
Complete all three campaigns on 'Hard' difficulty
Survive multiple waves after the download completes in 'Fact Finder'
Don't lose any units during the first attack in 'Prime Target'
Play the game for over 24 hours in total
Win 25 skirmish matches