Here is the full list of all 12 Archaica: The Path of Light achievements.
Find and activate all Megaliths.
Activate all Lightwells.
Activate Stone Keys in 10 levels.
Find and collect the Dark Crystal for the Almanach.
Put the Goddess of Fire into a deep slumber.
Complete 20 levels by finding all collectibles.
Find and activate the Primal Well in the Desert City.
Complete one of the Great Realms without using a hint.
Collect 15 Cells.
Complete the Initiation Ring and activate the Realmgate.
Collect 15 devices for the Almanach.
Collect chronicles from 3 realms.