Here is the full list of all 20 Onirike achievements.
Collect all the gypsophila petals of the orb
Collect 20 gypsophila spores in a single day
Open the Well of Truth
Reach the top of the great volcano
Gather the 7 fragments of the key to the Well of Truth
Complete the pizza of the Putrid Zone
Open the bamboo door
Cross the chessboard with 5 knight moves
Light the Sea of Doubt Lighthouse
Empty the Sea of Doubt
Plant 100 gypsophila flowers
Cross over to the other side of the magic doors
Make smoke come out of your head
Use the power of illusion 20 times
Get the eye of the wolf
Get the cardboard village train going
Open the door of the ribs door
Collect 100 gypsophila petals
Unveil the secret of the stone heart
Free the clown from the puppet's strings