Here is the full list of all 41 Little King's Story achievements.
Have 50 Children in Your Kingdom
Find All Hot Spring
Find 50% Hot Spring
Kill 500 Creatures
Have 20 Children in Your Kingdom
Have 10 Children in Your Kingdom
Collect 50 Paintings
Execute 50% Kingdom Plan
Collect 10,000,000 Bol
Break 50% obstacle
Collect 1,000,000 Bol
Find 50% Treasure
Collect 100,000 Bol
Pay 2,000,000 Bol for Condolences Solatium
Collect 10 Paintings
Clear 50% Quest From Suggestion Box
Kill 100 Creatures
Execute 10% Kingdom Plan
Pay 200,000 Bol for Condolences Solatium
Pay 1,000,000 Bol for Condolences Solatium
Break 10% obstacle
Find 10% Treasure
Kill 50 Creatures
Clear 10% Quest From Suggestion Box
Find 10% Hot Spring
Clear All Quest From Suggestion Box
Clear All Quest From Princess Apricot
Clear All Quest From Princess Bouquet
Clear All Quest From Princess Spumoni
Clear All Quest From Princess Shizuka
Clear All Quest From Princess Kokomo
Clear All Quest From Princess Ferne
Clear All Quest From Princess Martel
Execute All Kingdom Plan
Find All Treasure
Collect All Paintings
Break All obstacle
Complete the game on Easy difficulty
Complete the game on Normal difficulty
Complete the game on Hard difficulty
Complete the game on Hell difficulty