Here is the full list of all 36 TUNIC achievements. It takes around 15-20 hours to unlock all of the achievements on Windows.
Completed the Manual
Found Secret Treasure #7
Found Secret Treasure #6
Found Secret Treasure #1
Found Secret Treasure #8
Freed a friendly fairy
Restored corporeal form
Earned the Cathedral's Prize
Made a wish
Completed key collection
Found the red key
Found the green key
Found the blue key
Froze yourself
Chopped down 1000 blades of grass
Engaged a strange device
Rang the Western Bell
Understood the margin of page 17
Made an offering
Perfectly executed a special technique
Was resurrected
Rang the Eastern Bell
Found a sword
Found a stick
Found your rightful place
Found Secret Treasure #2
Found Secret Treasure #3
Found Secret Treasure #4
Found Secret Treasure #5
Found Secret Treasure #9
Found Secret Treasure #10
Found Secret Treasure #11
Found Secret Treasure #12
Had 10 moneybanks at once
Made 15 wishes
Found a certain weapon before getting a sword. (Page 38)