Here is the full list of all 25 Untitled Goose Game achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
Make the shop scales go ding
Earn every other trophy
Trip the boy in the puddle
Make someone from outside the high street buy back their own stuff
Trap the boy in the garage
Get thrown over the fence
Perform at the pub wearing a ribbon
Steal the old man's woolen hat
Collect the five flowers
Complete the back gardens to-do list
Finish the game
Complete the back gardens to-do list before the church bells ring
Cabbage picnic
Complete the pub to-do list before the church bells ring
Complete the pub to-do list
Dress up the bust with things from outside the back gardens
Score a goal
Sail the toy boat under a bridge
Catch an object as it's thrown over the fence
Open an umbrella inside the TV shop
Complete the high street to-do list
Complete the high street to-do list before the church bells ring
Lock the groundskeeper out of the garden
Complete the garden to-do list before the church bells ring
Complete the garden to-do list