So, you might be asking, what is a reward mechanic? Well, a reward mechanic is essentially a system to reward players playing a game that they have completed a section of.
Below is a link to a video on what gamification is to professionals. Gamification is essentially the process of game thinking and game mechanics to solve problems and engage users.
A reward mechanic can be in various forms. For example, games may have virtual coins that can be then used to purchase better in-game items. Another method is experience points, which can be gained through completing various activities throughout the game. The more points a player earns, the better the skill level of that player will be.
Another form of a reward mechanic is in shooting games, where if a player receives a certain number of kill in a row, they receive bonuses. In this example, a player receives bonuses for killing other players in a row, as well as all the other rewards that players can receive whilst playing Call of Duty.
Reward mechanics are used to keep players interested in a game. It can be simple as Tetris, where points are used in order for the player to beat its previous high score.
Gamification.org has a list of various reward mechanics that various games use in order to keep players interested.
One blogger that I’ve found has his take on reward mechanics and what they do. He explains that they are like a giant sign, which points the player into the direction that the best way to play is.
Hopefully this gives you a better idea on what reward mechanics are and how they work.