How the designers of Candy Crush maintain the balance between monetization and fun

In Candy Crush, players who watch ads are always rewarded with in-game bonuses, such as “boosters” that make levels easier to beat — which means workers at Activision Blizzard Media, the corporation’s in-game advertising arm, must regularly coordinate with King’s level designers to make sure ad-rewarded boosters don’t make any levels too much of a breeze.