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