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