Here is the full list of all 47 Ancient Planet achievements. It takes around 12-15 hours to unlock all of the achievements on Windows.
Shoot down 150 storm troopers
Shoot down 10 storm troopers
Demolish attack obelisk
Stop the incubator
Free Aludrians from 200 jellyfish
Demolish any 200 objects on the map
Save the planet from 20 reanimators
Build 20 support towers
Kill one reanimator
Demolish armor obelisk
Destroy 10 000 enemies
Collect 1 000 gold units
Demolish health obelisk
Build 80 factories
Stop Phoenix
Destroy 5 Aludrian mines
Build any 500 towers
Collect 20 000 silver
Kill 500 doctors
Kill 300 spiders
Build a support tower
Crash 100 destroyers
Destroy any 50 objects on the map
Abolish any 10 objects on the map
Kill 100 doctors
Collect 200 gold units
Send to the skies 2 000 enemies
Build ten energy towers
Kill 300 scouts
Build any 50 towers
Send to the skies 150 Aludrian officers
Destroy the destroyer
Raze the fallen missile to the ground
Kill 1 000 enemies.
Kill 150 troopers
Kill the first Aludrian!
Build one energy tower
Build three factories
Build two machine-gun towers
Kill the first attacking Hamalian!
Collect 50 000 silver units
Build 50 missile launchers
Demolish speed obelisk
Brew up 100 tanks
Destroy Emperor's pedestal
Save the planet from the democracy lantern
This honorary rank is given for 30 000 killed enemies