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