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