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