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
Complete Thorn quest
Hatch the God Egg
Collect all Wickerlings
Unlock all treasure chests
Complete the story
Collect every ability upgrade
Complete Willo's quest
Complete Rinri's quest
Toot the noisemaker 1000 times
Become the Postmaster
Get the biggest wallet
Deliver the cake to the inventors house
Try every ball style
Defeat Screetch
Complete the temple trials
Unlock all the Beelines
Discover the heart cluster at the bottom of the sea
Discover Fosfor’s Lair
Collect the Divefish
Defeat the Spider
Befriend a Sootling
Customise Yoku’s ball
Take the surviving egg to Dipperloaf
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