You can feed Rhee on different difficulty levels. The higher the difficulty level, the more treats you’ll need to use to make the monkey full and the bigger your total reward will be. You can select a difficulty level from Rhee’s window.
Difficulty levels are unlocked gradually. By feeding Rhee on simple difficulty, you’ll start unlocking the next difficulty level. Once you open all the difficulty levels, you’ll be able to select any one of them.
The higher your difficulty level, the better the reward for winning.