Here is the full list of all 32 The Count Lucanor achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
Get the fire room letter without using the bucket of water.
Enter the fire room from a secondary door.
Find the castle's wall at day.
Discover the truth in the throne hall.
Catch the butterfly in the depths.
Feed the worm from the depths.
Guess the kobold's name using the letters.
Open the garden chest.
Catch Eisbein.
Kill the old woman and Eisbein.
Use the snake ring at the best place.
Find J.F.'s most important note.
Find some stale bread before night falls.
Find the chest hidden near your house.
Guess the kobold's name without using the letters.
Find the hidden treasure of the Count.
Get the treasure hunter badge from Giulia.