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