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