Here is the full list of all 39 Spiritfarer achievements. It takes around 35-40 hours to unlock all of the achievements on Windows.
Accomplish your very last objective
Bring all releasable spirits to the Everdoor
Use Alex's bus stops 50 times
Activate all the shrines
Give a dating advice
Build all houses and stations at least once on the boat
Complete all collections
Collect all figureheads
Fully improve Elena's Cubicle
Discover all recipes
Make all spirits reach the ecstatic mood at least once
Find and shelter all sheeps
Light up all Lighthouses
Fully improve Buck's Lair of Wonders
Have your final conversation with Hades
Endure 10 of Albert's jokes
Fully improve Gustav's Gallery
Fully improve Atul's Workshop
Fully improve Stanley's Playroom
Have your second conversation with Hades
Unsubscribe from Feedorama
Shear sheeps at least 50 times
Do not tell Astrid about Giovanni's night excursions
Tell Astrid about Giovanni's night excursions
Complete thirty errands for Francis
Fully improve Bruce and Mickey's Crib
Fully improve Astrid's Bungalow
Sell at least 200 items
Complete twelve errands for Francis
Fully improve Alice's Cottage
Make 5 spirits reach the ecstatic mood at least once
Fully improve Summer's Sanctuary
Buy at least 100 items from Raccoon Inc
Sign up to Feedorama
Have your first conversation with Hades
Complete one errand for Francis
Fully improve Gwen's Lodge
Give Furogawa Tour's guide a tip
Make one spirit reach the ecstatic mood at least once