Quests

Once you make a little progress into the game you can start earning gold and diamonds from quests. A quest icon bubble appears on the top left side of the screen next to the menu icon and monster information icon. You are given 3 quests at a time and upon completing the 3 quests (there is no time limit), you earn a completion reward that is around from 1-7 diamonds. Quests may include:
 * taming a certain number of one type of animal
 * selling a certain number of one type of animal
 * buying a certain number of one type of animal
 * killing a certain number of one type of animal

The first three quests are exiting the cave, killing 3 mice and tame 1 mouse, being worth 100 gold for each one and 10 diamonds once you complete them.

Quests can be changed by watching an ad. Then there is a cooldown of 4 minutes 30 seconds before you can change a quest again. The rewards for the quests themselves is usually gold, but can occasionally also be a small amount of diamonds.