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