Variable Reward Can Hook Players For Replay

As Nir Eyal, author of Hooked and developer of the Hook Model, points out, “we are driven to conquer obstacles, even […] when we don’t outwardly appear to enjoy them,” and that, “adding an element of mystery to this goal makes the pursuit all the more enticing.” This observation certainly explains why some folks love to play slot machines or even enter into the ever popular Powerball lottery. There’s something ever so tantalizing about playing these games, getting a near win, and still not even winning!

## Examples

### Pixel Galaxy

Similarly, in Pixel Galaxy, you never know exactly what sort of experience you’re going to get. Each level has some randomized enemy pixel generation, and you cannot predict what will happen next in any level like you could in Galaga or Super Mario Bros. Consequently, you have unique opportunities to create ship configurations each attempt. Some enemy pixels wield pixel swords, others leave a trail of damaging pixel death, and others simply shoot deadly pixels. If you contact that pixel directly, you will acquire it, so its effects now become yours. The risk involved in acquiring any of these pixels and the reward you acquire when you integrate these onto your accumulating pixel ship gives players a stimulating and unique experience each play. This unpredictability of the level design can at times be frustrating, but this variety in ship configuration makes continued attempts much more tantalizing.

As a player, this element of surprise drives you back and back again, and as a game developer, this same element of surprise creates a powerfully rewarding experience your players will enjoy. Take a lesson from Pixel Galaxy, and think about how you can include this element of *variable reward* in games you design as well.

### Destiny

   The game Destiny uses the concept of variable reward in their loot system. Every time you kill an enemy loot is dropped at random. This loot is randomized and can range from common items to legendary items. The rewards the player receives from boss fights and raids is also randomized. This sense of uncertainty to see what type of loot one will get from killing enemies, opening chests or completing a raid keeps players engaged and coming back for more.

Example: Binding of Isaac Rebirth

In the game Binding of Isaac: Rebirth, a lot of stuff in the game: the maze of every level, power ups, enemies & bosses, are randomly generated. Some power ups are very useful, some power up can rise the protagonist’s attributes permanently, while other power ups can have a negative effect or force players change the way they play. This design makes player’s experience different every time they play the game, also makes player come back again and again in hope that they would get lucky (which never happens to me at least).

### Risk of Rain

Risk of Rain is a great rogue-like 2D action game. In the game, there are more than fifty different powerful items in the game. In a randomly created game level, you will have possibility to randomly get them as reward when you reach some location or kill some monsters. Since there are a lot of funny functions in these items, for example, the electrical shield can do damage to monster around you, the sand clock can prevent you from death if you were in danger, it is super fun to try again and again to collect them.

I have played many times with my friends, each time, I got different game experience with different items combinations. We have different occupations in the game and there was an inspiring experience when we get items which have reactions with our skills. Variable reward items in the game is an important system which makes Risk of Rain a fantastic game.