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.
Level up your Hero to level 21
Complete 3 quests
Level up your Hero to level 16
Create all elements in Main Game
Invent all spells
Buy 10 belongings for your Hero.
Buy some equipment for your Hero
Create all magical creatures.
Level up your Hero to level 10
Open all elemental elements
Create all 3 towns
Level up your Hero to level 1
Level up your Hero to level 4
Complete 1 quest