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