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