[Chelsey Webster explains how a skillfully implemented reward structure can enhance a player's experience and make a game more enjoyable throughout.]
Rewards are an important feature of any game, and as such, can be found everywhere across all genres. Rewards can come in any shape or size, and when given to the player appropriately can greatly increase their enjoyment of a game, motivating them to continue to play.
Rewards can even have a player do something that they don't want to do, or don't enjoy doing (which is quite opposite of the purpose of playing a game). Many players will do annoying, tedious or boring things for rewards. The ability to have a player do what they dislike of their own volition attests to their power. They are an essential tool to a designer.
Designing Reward Structures
Rewards shouldn't be included on a whim; they must be scheduled and structured. The following diagram is a hierarchy of needs, adapted for reward structures.
Fig 1: Hierarchy of Rewards in Games
Based on Maslow's Hierarchy of Needs, each section is a prerequisite to the one above, and can greatly enhance the one below. If a section is missing, however, those above it become ineffective. When designing a reward structure, it is important to work from the bottom of the hierarchy upwards to achieve a solid foundation. It is therefore important that each section is linked to the next. The higher up in the hierarchy, the more frequently the reward should be distributed; a fractal-like pattern should emerge (i.e. 10 minor rewards = 1 major reward, 10 major rewards = 1 core reward). It doesn't have to be strictly fractal of course, but minor rewards should considerably outnumber major rewards, and so on.
As we move upwards through the hierarchy, rewards become less intrinsic/more tangible. The bottom of the hierarchy is the most fundamental and intrinsic of rewards to the player - the player experience. At the other end of the scale, the top is purely cosmetic and cannot exist without the rewards listed below - however it works to enhance those below. Think of a scope for a rifle. The scope is great, and makes the gun much better; but it is completely worthless without the gun.
The following gives an overview of each section of the hierarchy and what kind of rewards may be found therein. Examples here will often be of the kind found in adventure or RPG games, but the principles can be applied to any genre. The rewards structure should always be designed in order of importance - from bottom to top.