Here is the full list of all 19 Planetary Annihilation achievements.
Build every structure in a single game
Kill a commander within five minutes, five times
Keep tabs on your conquest with ten camera anchors
Build every kind of unit
Participate in ten team games
Manage your armies with all ten control groups
Smash five enemy planets
Discover a new loadout in galactic war
Annihilate your opposition throughout the galaxy
Win against three times as many players
Destroy five enemy planets with annihilasers
Use more than 95% of the metal and energy you produce in a match
Eliminate a faction in galactic war
Build every kind of basic factory
Start a game with a custom system
Activate an annihilaser
Target an incoming planet with an annihilaser
Watch competitive play for two hours as a spectator
Watch competitive play for eight hours as a spectator