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.
Complete one of the Great Realms without using a hint.
Complete 20 levels by finding all collectibles.
Find and collect the Dark Crystal for the Almanach.
Put the Goddess of Fire into a deep slumber.
Collect 15 devices for the Almanach.
Collect chronicles from 3 realms.
Collect 15 Cells.
Complete the Initiation Ring and activate the Realmgate.
Find and activate the Primal Well in the Desert City.