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
Unlocked all of Etna's alchemy recipes
Reach Level 75
Reached the Ruined Arena
Reached the Prison
Reach the Castle
Reach Level 50
Find the Second VHS Tape
Reach the Catacombs
Slay an Abyssal Demon
Reach the Lake
Reach the Sewer
Reach Level 25
Reach the Forest
Reach the Grand Library