Here is the full list of all 26 Lunacid achievements. It takes around 20-25 hours to unlock all of the achievements on Windows.
Wake the Old One
Reach Level 75
Unlocked all of Etna's alchemy recipes
Reached the Ruined Arena
Reach Level 50
Reached the Prison
Reach the Castle
Find the Second VHS Tape
Slay an Abyssal Demon
Reach Level 25
Reach the Catacombs
Reach the Lake
Reach the Grand Library
Reach the Forest
Reach the Sewer