Here is the full list of all 30 Once on a windswept night achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
Name yourself after a certain flower.
Arrange the actors back on the stage.
Wait for a play that's already over.
Reach your happy ending.
You remember who you are.
Read a lonely spirit's story.
Bring the story to a premature close.
Read Daffodil's story.
The traveller refuses to tell Daffodil the truth.
Offer Daffodil a few too many compliments.
Read Madeleine's story.
Madeleine refuses to share her story.
D-Did you just insult a girl's cooking?! You monster!
Throw caution to the wind!
Listen to a mysterious voice.
The traveller leaves the church early.
Let yourself forget everything.
Return to the library for a second time.
Start a new story.
Lycoris welcomes you to her library.
Try to steal Lycoris' most precious possession.
Multiply the number of daffodils in the story.
Make yourself the third Madeleine.
Take the traveller's name for your own.
Answer Lycrois' question incorrectly.
Lycoris gets a little too possessive.
Return to the library when Lycoris needs you the most.
Learn Lycoris' favourite flavour of tea.
Profess your love for Daffodil.
Profess your love for Madeleine.