Here is the full list of all 21 Garden Story achievements. It takes around 12-15 hours to unlock all of the achievements on Windows.
Vanquish the Grove's Clutch.
Complete Goldie's Favor.
Defeat 50 Snowcaps.
Defeat 50 Hayrots.
Defeat 50 Glomps.
Upgrade a jar to Grade 4.
Upgrade a tool to Grade 4.
Defeat 50 Shelled Oozes.
Obtain the Silversword
Defeat 50 Acorns.
Arrive in Winter Glade.
Obtain the Flute.
Roll 100 times.
Defeat the Rotberg once.
Take the Lift to Autumn Town
Defeat the Octopihi once.
Reach the Summer Bar
Defeat the Bookworm once.
Defeat 150 Enemies.
Reduce the Rot Dummy to rubble.
Wake up in Spring Hamlet.