Here is the full list of all 25 Interplanetary achievements.
Build 200 buildings on your planet.
Defeat two enemy planets in one turn.
Beat the Impossible AI.
Unlock all technologies.
Have your planet run out of material.
Fire all the superweapons during the same turn.
Hit your own planet with a railgun.
Produce 7,000 Energy in one turn.
Have 25,000 material in stock.
Grow five cities to their maximum populations.
Defeat an enemy planet.
Fire Solar Laser superweapon.
Fire Asteroid Diversion superweapon.
Win an online multiplayer match.
Win 5 online multiplayer matches.
Win 10 online multiplayer matches.
Win 50 online multiplayer matches.
Win 100 online multiplayer matches.
Win 10 single player games.
Win 100 single player games.
Win an online multiplayer match with at least two players.
Win an online multiplayer match with at least four players.
Win an online multiplayer match with eight players.
Destroy 100 cities over any number of games.
Win a match with barely any population left.