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