Here is the full list of all 56 Home Sheep Home 2 achievements.
Find a hidden cake to unlock a special bonus mode
Complete Underground level 1
Find two missing wooly socks
Complete Ewe-niversity training
Complete Further Ed-ewe-cation training
Complete Graze School training
Complete Underground level 5
Complete Underground level 10
Complete Underground level 15
Complete London level 1
Complete London level 5
Complete London level 10
Complete London level 15
Complete Space level 1
Complete Space level 5
Complete Space level 10
Complete Space level 15
Complete any one bonus level
Complete any five bonus levels
Complete any ten bonus levels
Complete all bonus levels
Complete all episodes
Find a giant cake to unlock developer commentary
Toast Shaun on a rocket in the last space level
Complete London level 1 with the luggage on board
Smash 5 speed cameras in a row in London level 3
Get a photo of every sheep in London level 3
Complete London level 5 with all chimneys intact
Use just 2 'chutes to survive the mineshaft fall
Complete Underground level 4 without using any TNT
Complete Underground level 6 with TNT to spare
Solve Space level 4 with only two teleport swaps
Change sheep selection just once in Space level 14
Surf the camper van home in London level 15
Cross Big Ben's clockface without moving the hands
Get all three sheep flying together using the chimney
Don't touch the football in Space level 6
Complete any level with a three star rating
Complete five levels with three star ratings
Complete thirty levels with three star ratings
Complete all story levels with three star ratings
Beat the developers' time on any one level
Unlock the London episode by finding 12 socks
Unlock the Space episode by finding 24 cosy socks
Find fifty socks, enough for any sheep
Find seventy five socks, a lifetime's supply
Find every wooly sock in the game
Unlock a bonus level by finding a hidden joypad
Find every hidden cake to unlock all bonus modes
Find every joypad to unlock all bonus levels
Collect everything possible from every level!
Achieve every other achievement
Complete Farm level 1
Complete Farm level 5
Complete Farm level 10
Complete Farm level 15