Here is the full list of all 14 Doodle Kingdom achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
Buy 10 belongings for your Hero.
Create all elements in Main Game
Buy some equipment for your Hero
Level up your Hero to level 1
Level up your Hero to level 4
Create all magical creatures.
Level up your Hero to level 10
Open all elemental elements
Invent all spells
Create all 3 towns
Complete 3 quests
Level up your Hero to level 21
Complete 1 quest
Level up your Hero to level 16