Here is the full list of all 15 She and the Light Bearer achievements.
collected all light bearers in credit scene
all achievement
completed chapter 5
completed chapter 4
witnessed mushroom sacrifice
found all secret carvings
completed chapter 3
collected all snails
used cucumber on potato
answered all riddles
slapped by mushroom 10 times
completed chapter 2
completed light 'n orb test
scared orchid with snail
completed chapter 1