Here is the full list of all 31 Yoku's Island Express achievements. It takes around 10-12 hours to unlock all of the achievements on Windows.
Complete Thorn quest
Activate all Scarabs
Get the biggest wallet
Unlock all treasure chests
Collect every ability upgrade
Complete Willo's quest
Try every ball style
Complete Rinri's quest
Hatch the God Egg
Collect all Wickerlings
Become the Postmaster
Toot the noisemaker 1000 times
Deliver the cake to the inventors house
Take the surviving egg to Dipperloaf
Complete the story
Defeat Screetch
Complete the temple trials
Discover the heart cluster at the bottom of the sea
Discover Fosfor’s Lair
Customise Yoku’s ball
Defeat the Spider
Unlock all the Beelines
Befriend a Sootling
Save Spina
Collect the Divefish
Ride the Beeline
Suck up a slug with the Slug Vacuum
Find the Post-office
Free Kickback
Toot the noisemaker 100 times
Blow the noisemaker