Here is the full list of all 12 Archaica: The Path Of Light achievements worth 1,000 gamerscore.
Complete the Initiation Ring and activate the Realmgate.
Complete 20 levels by finding all collectibles.
Put the Goddess of Fire into a deep slumber.
Collect 15 Cells.
Find and collect the Dark Crystal for the Almanach.
Complete 40 levels by finding all collectibles.
Collect 15 devices for the Almanach.
Activate all Lightwells.
Find and activate the Primal Well in the Desert City.
Activate Stone Keys in 10 levels.
Find and activate all Megaliths.
Collect chronicles from 3 realms.