Today’s article is the second one in the series “Game Theory Applied”. You can find the first article of the series here. Today I would like to talk about game rewards, and how I applied them on New Sokoban.

Game rewards are a very important concept in game design. Actually, in some sense, players play games to be rewarded. It is a human need. Players need to be evaluated favorably. That’s why a well designed and balanced game rewards system is key in any game, even for the simplest one.

There are lots of kinds of game rewards that could be included in a game: praise, points, prolonged play, spectacle, powers, resources, completion… In general, you should include as many rewards as you can. However, never forget that game rewards must be balanced. You need to give the right reward, at the right time and in the right amount.

When designing New Sokoban I tried to include different types of game rewards. However, I focused on two more general issues that drove the design process of the rewards system of New Sokoban:

• Rewards vs. Punishment
• Casual Gameplay vs. Hardcore Gameplay

A layered game rewards system design

So, my aim was to offer a game reward system that included rewards for both casual and hardcore players while avoiding punishment. To achieve that, I designed the game rewards system in layers. A layered rewards system design means that the player initially only sees the obvious objectives and gets the obvious rewards (the firsts layers) but after playing a while, he starts to discover that there are some more complicated challenges with more satisfying rewards.

The idea is not to overwhelm casual players with tons of “impossible” game rewards to achieve but at the same time give the opportunity to hardcore players to discover the hidden layers with the more rewarding challenges. Actually, discovering the hidden layers is a reward itself for a hardcore player.

So, the player starts by encountering the basic objective: solve the puzzle. Simply solve it. This is the first layer. The reward is the satisfaction of completion, the praise in the rewards screen, the score and the following puzzle that is unlocked.

At this moment the following layer is presented clearly: if you solved the puzzle with less than 3 stars you will see unfilled stars on the rewards screen that claim to be filled. That’s layer two. Moreover, if you wait a moment, you will see all the bonuses you earned and how they add to your final score. That is rewarding for hardcore players as they always want higher scores.

The bonuses system adds some more layers. Every player will pay attention to the bonuses he is interested on. Casual players will just skip this screen after seeing the number of stars achieved. Hardcore players will examine all the bonuses earned and wonder if they could improve their score based on the score system of the game. Understanding the score system is an interesting challenge for a hardcore player with a great satisfaction reward when it is achieved.

So, only after playing a few puzzles every player has established his own objectives based on the game rewards he wants to achieve. Casual players will keep just solving puzzles. With 1 star, doesn’t matter. Some other players will go for the 3 stars for every puzzle. Others will try to maximize score, others will fight for the first row at Game Center leaderboards… Actually, theoretically, all the players may go throughout all theses phases eventually. Ones earlier than others.

The “hidden” layers

So, to say it short, the casual player “only” needs the game to be fun. Most casual players are satisfied simply solving some puzzles (and skipping others). So, you “only” need a good game to satisfy casual players.

However, hardcore gamers need more. Obviously, they need a fun game but also a challenging one.

Next, you have some of the most interesting “hidden” layers of New Sokoban.

The bonus system

Initially New Sokoban was pure punishment 😀 You take too long to solve a puzzle, you get punished. Used the undo option? You get punished. Used the restart option? You get punished. Hardcore players tolerate certain level of punishment in games. Actually, punishment enhance endogenous value in some sense. However, casual players hate to be punished by games. So, New Sokoban needed to be “positivated”, rewarding players instead of punishing them.

The advantage of positive balancing (rewarding) is that nobody hates it. Both casual and hardcore players love it. There are some types of games that need a minimum level of punishment to make sense. For example, games based on “lifes”. If you fall down you lose a life. If that mushroom touches you, you lose a life. However, New Sokoban is not that type of game. Actually, New Sokoban can be designed without any kind of punishment. And that was the way I finally followed. New Sokoban went from hell to heaven 😀

And the bonus system was born. All punishing features were reconverted to bonus ones. So, when you complete a puzzle the rewarding screen informs you about all the bonuses you acquired: time bonus, no undo/restart bonus, etc. And all the bonuses are translated to points that are added to your final score. The bonus system worked really well.

Moreover, the bonus system may be easily ignored. It can even be partially ignored. You decide which bonuses you are interested in and forget about the others.

The under par system

The under par system was added in the final stages of development. Hardcore testers were claiming for more complicated challenges with really satisfying rewards. And the under par system was created for that. Believing that 3 stars is the best possible solution and then discover that you solved one puzzle under par is very satisfying for a hardcore player.

Moreover, under par solutions adds a great score bonus to the puzzle final score.

The whole score system. Discovering how to get the best score possible

Initially, the score was based on the moves the player needed to solve the puzzle. Then, I added the bonus system. However, I needed a way that players fighting for the first position on Game Center could differentiate from each other. A system based on moves, stars or fixed bonuses produced very similar scores from player to player.

So I added the time bonus. Every puzzle records the time elapsed to solve it in tenths of a second. The final time bonus score is not calculated with a linear function. Instead of that I used and exponential one. That way, the time bonus score for long periods of time tends to be the same but you have tenths of a second precision for short periods of time (a few seconds). So, it’s almost impossible that two players get exactly the same score on Game Center.

This kind of precision adds interest to the Game Center leaderboards and makes the whole score system (moves, stars and bonuses) take a bigger dimension.

Game Center

Game Center in New Sokoban is the rope that tie everything together. Everything is related: moves are related to stars. Stars are related to score. Score is related to bonuses. Bonuses are related to achievements. Achievements are also related to leader boards and leaderboards are related to score again.

It’s a nice and elegant cycle that works really well.

Conclusion

I think that the time I spent designing the layered game rewards system of New Sokoban was worthwhile. The final result is elegant and almost every type of player feels comfortable with the rewards he receives.

Mental note: a very simple game with a sophisticated and well balanced rewards systems offers the best of the two sides: simplicity for casual gamers and challenge for hardcore ones.

This post is part of iDevBlogADay, a group of indie iPhone development blogs featuring two posts per day. You can keep up with iDevBlogADay through the web site, RSS feed, or Twitter.