作者：Richard Rouse III

本文节选自Richard Rouse III的书《游戏设计：理论与实践》（ Game Design: Theory & Practice），其中涉及若干关键的游戏设计论题，即原作者所谓的“游戏玩法的元素”。该书涵盖了游戏设计的方方面面，从有效创意的产生到设计文案的书写，从玩法的执行到成品的测试，可谓内容丰富、覆盖面广。

“结果我们做出来的游戏连我自己都不知道怎么赢。即使游戏所有系统都出自我的手笔，我还是不知道什么是取胜的最佳策略。优秀的策略游戏就应该是这个样子。”—–Julian Gollop如此评价他的游戏《X-Com: UFO Defense 》

什么样的设计元素能成就一款真正的好游戏？当然，这个问题的答案是无穷无尽的。尽管如此，作为游戏设计师的你仍然应该对此答案有一个直觉上的精准定位。理解游戏设计，犹如欣赏某种艺术形式，是一种内在化的认知，只可意会，不可言传。你可能没有办法字字句句地说出来，但你必须明白游戏的哪方面强烈哪方面薄弱，以及如何扬长避短、化劣势为优势。理解好游戏为什么好玩，体验发挥了重要的作用，这里的体验包括游戏设计师的体验和玩家的体验两个方面。

根据我数年的玩游戏和设计游戏的经验，关于怎么让游戏好玩，我总结出了一套自己的答案。在本文中，我将就此展开论述。有些观点虽显而易见，但就我看来，我所列举的方面都在好游戏中扮演了关键角色。当然，我不能指望用一篇文章就将自己的全部想法和盘托出，因为我理解大多来自“第六感”，比书中所写的其他内容更感性。但本文所述的想法应该能给你一些启发。

不走寻常路

对我而言，当游戏设计师最令人兴奋的时刻之一就是，听到有人在讨论我的某款游戏时谈到如何用一个成功的策略解决某种情况，而那个方法我自己从来就没想过。那个情况可能是一个特定的谜题，一种击败敌人的方法，或者越过危险峡谷的途径。我把自己开发的游戏看作创造的情境，玩家可以在游戏中运用自己的创意获得成功。当玩家靠自己的创意找到某个连我都始料未及的解决方法时，那就能说明我的游戏不负所望了。

预期与复合系统

好设计师会努力琢磨玩家的心思，然后让自己的游戏响应玩家的行动。以一款RPG游戏为例。该游戏中有一个谜题是要求玩家在压力盘上加重。（游戏邦注：作者认为如果把这种谜题放在他自己的游戏中，他会要求设计师多发挥点创意，毕竟压力盘这种设计已经被用滥了。）考虑到设计师在压力盘附近放了那么明显的石块，那么答案显然就是将石块放到压力盘上来达到适合的重量。但是，如果玩家不用石头，而是丢盔卸甲把压力盘所需的重量凑足呢？这确实是一个无懈可击的解决方案，应该也管用，如果玩家的装备恰好达到合适的重量的话。倘若玩家正好精通召唤术，能够召集各种各样的小怪？假如玩家让小怪站到压力盘上，应该也凑效。现在，如果设计师已经通盘考虑过这些情况，然后让程序师把相应的代码加进去，即无论是石头还是武器或是小怪，游戏都能作出正确地响应。这是一种游戏设计的预期：设计师事先想到玩家可能做出的举动，让游戏能够成功地应对这三种情况。我认为这种策略肯定比单一的解决方案高明得多。然而，如果玩家实在太有才了，居然想到放其他东西上去呢？比如，玩家念起了暴雪咒语，把雪堆在压力盘上呢？只要雪够多，肯定也能达到所需的重量。但是，如果游戏只能响应石头、武器和小怪这三种情况，遇上雪，游戏就不能正确地响应了。也就是，玩家想到的完美无缺的解决方案，而游戏居然无法识别。

好吧，放弃硬性规定，设计师让程序员重新编写一种系统，允许游戏中的任何物品都有一个相应的重量。也就是，包括石头、武器、怪物、天气作用、血液等等，所有在游戏中能找到的东西。如果程序师让压力盘只是简单地接受堆积在上面的重量，而不管该重量的类型，那么，这个谜题的解决方法就是五花八门的了。如果各个物品都有一个合理的重量，那么无论玩家把什么物品放到压力盘上，游戏都会自动响应。

后面这个方法就不太像游戏设计的预期系统了，反而更接近一种整体考虑。这个方法有赖于可靠的创意、游戏能运行的相容系统。然后，对于前文所述的压力盘之类的谜题，设计师和程序员想出一系列能满足谜题的条件。不是“这个谜题只能在压力盘上放石头、武器和怪物才算通过，”而是“这个谜题只需在压力盘上放置正确的重量即可。”当然，这个谜题的例子还是比较简单的，但相同的技术可以应用到更多更复杂更有趣的系统中，从而产生更丰富的游戏方式。

意外情况

《文明》中有许多复杂的玩法同时运行于多个相容的系统中(from gamasutra)

正是无数个强大而合理的系统的开发诞生了玩家们各自独特的解决方案。我们可以称这些解决方案为游戏系统开发中的“意外情况”（emergent），这是个游戏圈中的热门词。设计师应该建立一个根据逻辑来运转的游戏世界，在里面，玩家可以轻易地理解和发挥自己的优势，这样玩家才能针对某个问题想出自己的解决方案。这对玩家而言就是最大的奖赏，比尝试一些不显著不高明的方法去解谜或战斗更有价值。在越是复杂的系统之间，如果能正确同时地响应彼此，那么解决方案就会越有趣越丰富。游戏《文明》中有大量系统是同时运行的。这些系统共同组成了吸引人的游戏玩法。

另一个“意外情况”的例子可以在游戏《Centipede》找到。玩过这款游戏的人应该知道，堆蘑菇是最难完成的任务之一。许多玩家都知道必须尽可能地保持场地干净。当玩家一次又一次地“清场”后，开始发现其中的规律了。首先，他们认识到，跳蚤负责投下大多数有问题的蘑菇，另一小部分则是打蜈蚣时落下的。再者，玩家注意到游戏的跳蚤从来不出现在第一波。第三，玩家观察到如果屏幕下部分的蘑菇消失了，跳蚤就会出现。这样，一个著名的策略就诞生了，这个策略甚至是游戏的设计师Ed Logg都从未预料到的。运用这个策略，玩家可以在第一波时清掉所有蘑菇，然后只允许屏幕下方右半边的蘑菇继续存活着。如果，玩家好好杀蜈蚣，只让那个四分之一部分的蘑菇生长，那么跳蚤就永远不会出现，这样游戏也就更简单了。这是一个获得高分的意外策略，玩家深感自豪发现了这么个妙法。此外，Logg作为游戏的设计师，甚至不知道有这么个策略存在。这真是个了不起的游戏设计。

非线性

非线性是游戏行业中的另一个热门词。非线性与游戏的有趣程度息息相关，可惜不少游戏设计师在工作中忽略了这一点。非线性提供的是交互活动意义，如果没有非线性，开发者们所做的充其量也就是电影罢了。游戏中的非线性成份越多，游戏就越精彩。

一般来说，当有人说什么东西是线性的时，他的意思就是该东西沿着线性发展。一条线也就是一系列在二维或三维空间中连结起来的点，如，在2D的条件下，y = mx + b所画成的直线。在外行人眼里，这意味着线必须是直的。比如线上有两个点A和B，那么这两点之间只有一条通过路径，没有其他选择了：要从A走到B，就必须依次通过每一个A与B之间的点。跳出数学运算的范畴，我们可以将线性体验比作阅读一本书。如果某人正在阅读一本323页厚的书，如果他没跳过某些页面或章节，那么读完全书的路线就只有一条，就是从第1页一直读到最后的323页。然而，游戏是非线性的。玩象棋时，吃掉对方将帅的方法有很多，从游戏预定位置移到到最终的位置的路线也不少。确实，象棋取胜的方法不胜枚举，所以这种游戏才会这么好玩。这些选择让象棋成为一种非线性体验。假定棋盘是一维的，而不是二维的，玩家的棋子只能朝一个方向前进，且每个玩家都只有一个棋。这样的象棋就是线性的，因为玩家没任何其他有意义的选择，每盘游戏的结果都是事先确定的。所以游戏也就完全没有乐趣可言了。

非线性的类型

所以当我们说到希望把游戏做成非线性的，意思就是游戏从开始到结束，始终为玩家提供更多从A到B的选择和不同的路径。我们可以从不同的方面定义非线性的类型：游戏的剧情，玩家应对挑战的方式或顺序，玩家选择的挑战等。所有这些都可以组成游戏的非线性内容，开发者创造的非线性内容越多，玩家的体验就越独特。另外，不同的线性成份可以互相作用，使整体的可玩性比个体之和更强。

剧情：非线性的剧情当然必须与非线性的玩法相关联。如果游戏本身提供给玩家的选择近乎没有，那么也没必要制作非线性的游戏剧情了。说到非线性，剧情大概是最容易被忽略的了，因为许多开发者虽然认同制作非线性的玩法，却没有给游戏提供完全线性的剧情。

解决方案：我在前面提到一款设计良好的游戏如何让玩家想出自己的一套解决方案。并非所有玩家都能想到一块儿去，并且既然这些不同的方法都是合理的，那么任何挑战都必须有不同的解决方法供玩家探索。一个挑战具有多个解决方案，这是非线性质一个大方面：让玩家可以有多种从A（当前挑战）走到B（解决方案）的路径。

顺序：除了可以通过独特的解决方案应对相同的挑战，玩家还可以选择挑战的顺序。许多冒险游戏要求玩家在给定的时间内完成确定的某个谜题，这种做法太过线性，是错误的。为了玩到后面的谜题，玩家必须完成当前的谜题。这是一种线性的思考方式，当玩家困在某个谜题中，因为游戏的线性属性，玩家能做的就是解决当前谜题，这种做法非常容易挫伤玩家。给予玩家不同难度的谜题选择，玩家可以先把有困难的谜题晾一边，先去解决其他的再回头看。完成第二个谜题后，玩家可能会回到第一个，稍作休息和调整，这时候的玩家更有可能解决这道路关卡。

挑选：另一个非线性的方法是允许玩家挑选其中一个挑战去解决。比如介于A与B之间的三个挑战XYZ，它们不是顺序的从属者，也就是玩家可以根据任意顺序选择挑战。如果玩家克服了挑战X，他就没必要返回去解决挑战Y或Z；玩家可以继续沿着B进行下去，也许再也不会回来解决Y和Z。如果玩家一开始就选择挑战Y或Z而不是X，那么结果也一样。玩家作什么选择都可以进行下去。优点在于，如果玩家发现挑战X太难了，他可以转而尝试Y或Z。这也极大地减少了玩家卡死在一个点上的可能性。不一定非让Y比X简单，因为不同的挑战本身已经给玩家提供了更好的选择，这取决于玩家的能力。有些玩家觉得X很难，而其他玩家可能会觉得X比Y或Z简单，给予玩家选择挑战的机会就是让玩家根据自己的能力去探索游戏，通过关卡。当然，完成挑战X后，玩家可能会返回来完成Y或Z，也许只是为了好玩，也可能是认为克服Y或Z挑战一定程度上会提升自己的能力，也许是觉得完成所有挑战可以使自己的角色获得更多的经验或财富。非线性的类型还可以用于增加游戏的可选副本。这些挑战不是完全需要玩家从头玩到尾，尽管他们可能会让游戏或多或少变得更简单，也可能只是提供了有趣的消遣。无论如何，这些选择性挑战增加了额外的非线性程度，进一步丰富了玩家的体验特征。

执行

Odyssey The Legend of Nemesis(from gamaustra)

（游戏邦注：《Odyssey》是一个非常典型的非线性游戏。它允许玩家以自己的顺序挑选希望继续进行的任务。几乎所有谜题的解决方案都不是单一的。）

我的第一款游戏《Odyssey: The Legend of Nemesis》，毫无疑问是我制作过的最为典型的非线性游戏，它包含了以上描述的所有非线性的类型。它是一款RPG，故事发生的地点是某群岛，其中玩家可以探索七座主要的岛屿。虽然玩家需要在第一座岛屿完成至少一个任务，才能继续游戏的其他内容，但玩家可以有两个起始任务可选，且各个任务均有多个解决方案。如果聪明的玩家发现抢劫某个居民的方法，甚至可以跳过整个任务。完成第一个任务或跳过第一个任务后，玩家可以自由地在接下来的五座岛屿中移动，随意选择自己想留下探索或路过的岛屿。当然，在玩家抵达第七座岛屿前，这些都是必须探索完的。游戏的结尾是玩家成功通过各岛屿，杀死挡道的怪物。当然，杀死怪物非常容易，如果玩家事先得到完成任务的奖励的话。但是，如果玩家这么做了，就可以跳过整个游戏的中间环节。当然，少有玩家会这么做，而宁可探索不同的任务和情境。几乎所有任务，玩家都有数个解决方案，无论玩家做出什么样的选择，都会对各岛屿的小剧情产生直接的影响。最后，游戏本身也有几个不同的结局供玩家探索，这些结局迎合了玩家的不同目标：生存、报复或正义与谐。尽管游戏的剧情是非常确切的，但我可以很高兴地保证，不会有两个玩家的游戏经过是一模一样的。在游戏设计中，非线性是一种非常强大的工具。以上所提到的非线性类型对读者来说，可能是显而易见的。但令人惊讶的是，有太多游戏根本没有给玩家带来实质性的非线性内容，而是坚持让玩家一条直线地从A走到B。原因之一是，制作非线性元素实在太耗时间了。想想，在A和B之间有XYZ三个挑战，但玩家只需完成其中之一就可以继续进程了，完全不必跟Y和Z产生什么联系。作为一款非线性游戏，这是玩家的特权。不过，当投资者统计游戏预算时，问题就来了。显然，如果Y和Z不是确实必要的，为什么要那么麻烦地制作这两个？为什么要在程序、美术和设计上砸钱，何况玩家有可能永远不会看到这两个？不幸的是，财务人员往往接触不到游戏设计的核心，当你说：“但非线性能让游戏有趣！”他们很可能因为你“执拗”鄙视你。

从设计的角度看，非线性不容易设计，肯定比线性困难。这可能是另一个导致许多设计师一开始就回避非线性的原因。设计无数个不同的障碍本身就已经够艰难的了，更何况还要把它们运用到相同的挑战中去。在XYZ挑战这个例子中，如果Z明显比X和Y简单，那相当有可能，没人会过问X或Y了。一定程度上，选项设计不佳的游戏基本上可以等同于没什么选项的线性游戏。游戏的非线性设置对玩家来说，必须有意义、有实在用处，否则就是浪费。有些设计师对自己的设计水平自视过高，选择避开非线性，因为他们希望玩家体验自己在游戏中加入的每一个元素。“为什么花那么时间在一个不是人人都会看到的部分上？”如果有哪位自大的设计师敢这么放言，那么他跟前面提到的财务人员也算是一条水平线上的了。

非线性的目的

记务必时刻记住，游戏中的非线性是为了给玩家带来游戏玩法上的有意义的自主权。如果强制玩家在游戏中一条直线走到底，那么玩家会觉得自己受限制被驱使。那条线上的挑战本身可能非常好，但如果玩家没有任何选择，只能按步就班地进行下去，一个接一个，游戏的乐趣势必会大大减少。

非线性是驱使玩家重复游戏的强大动力。重复玩一款已经通完所有关卡的游戏，并没有多大意思。而重玩一款非线性的游戏，玩家可以放弃上次游戏做出的选择，改走其他线路。然而，我们要注意到的是，重玩性不是把非线性纳入游戏设计的主要原因。我曾听说有些游戏设计师认为重玩性是没必要的，因为如此之众的玩家从来就不会对游戏“从一而终”。所以如果他们从来就不能完成游戏，为什么还要增加重玩性呢？这些设计师没有意识到非线性的要点在于，给予玩家身处游戏世界的自由感，让所有玩家都有自己独一无二的游戏体验可以跟别人分享。如果玩家想重玩游戏，那很好，但非线性的主要目的是交出一定程度的自主权给玩家。

此外，认为玩家极少完成游戏，因此没必要考虑重玩性，这个论点有失偏颇。玩家不能完成游戏的原因往往是因为他们卡在游戏的某个结点上了。可能是遇上一只太强大的BOSS怪打不过、也可能是一道太费神的谜题解不开、或者只是困在某个区域找不到出口。如果游戏更加非线性一些，玩家卡在游戏中的可能性就会大大减少，因为还有各种各样的路线可走，凭着玩家独有的聪明才智，总是能闯出一条活路来。

在游戏开发者大会上谈到的“A Grand Unified Game Theory”，Noah Falstein认为当非线性允许玩家根据自己的顺序来应对挑战时，完成一个挑战应该使玩家更有可能战胜其他挑战。在解谜题的情况下，这可以通过让已解开的谜题暗示玩家关于其他谜题的信息来实现。在战斗的条件下，这可以通过提供玩家额外的装备来实现。不论是什么情况，都可以采用该技术增加玩家克服挑战和继续游戏的机会。

注意：所有设计师应该明白非线性不是让玩家在游戏世界中漫无目的地瞎逛。如果游戏一点非线性都没有，让玩家不知道要怎么完成任务、怎么完成游戏，那么这个非线性也太过头了。通常游戏设计师会这么赞扬自己正在开发的游戏：“在我们的游戏世界，玩家可以随心所欲，无拘无束。游戏完全是非线性的！”诸如此类。这样的游戏也着实让人讨厌。当然，当这些完全非线性的游戏发布时，大部分非线性的内容都被剥除了，玩家只不过是沿着既定轨道解决一个又一个的谜题。自由只是相对的，玩家既该在游戏中自由行动，也应该受到指引避免迷失方向。

游戏邦注：原文发表于2001年6月27日，所涉事件及数据以当时为准。（本文为游戏邦/gamerboom.com编译，拒绝任何不保留版权的转载，如需转载请联系：游戏邦）

Game Design – Theory And Practice: The Elements of Gameplay

by Richard Rouse III

This excerpt from Richard Rouse III’s Game Design: Theory & Practice, covers several key game design issues, which contribute to what Rouse calls “The Elements of Gameplay.” The book covers all aspects of game design, from coming up with a solid idea to writing the design document, from implementing the gameplay to playtesting the final product.

“We ended up with a game that I didn’t know how to win. I didn’t know which were the best strategies or tactics, even though I designed all the game’s systems. That is what makes a good strategy game.”

—Julian Gollop, talking about his game X-Com: UFO Defense

What are the game design elements that make up a really good game? Of course, there is no definitive answer to such a question. Nonetheless, as a game designer you will be expected to intuitively know exactly what the answer is. Understanding game design, as with any art form, is very much an internalized understanding, a “gut” reaction, a “feeling” you might have. It may be that you will not be able to form that answer into words, but you will need to understand what aspects of a game are strong and which are weak, and how the latter can be replaced with more of the former.

Experience plays a big part in understanding what makes a game fun, experience both as a game designer and as a game player.

Over my years of playing and creating games, I have come up with my own answers for what makes a game great, and in this chapter I discuss some of those qualities. Some of these topics may seem fairly distinct from each other, yet to my mind they all play a crucial role in making a good game. Certainly, I cannot hope to list all of the knowledge I have, since, as I mentioned, much of my understanding is more akin to a “sixth sense” than anything I could hope to write down in a book. But the ideas contained in this chapter should help to give you a starting point.

Unique Solutions

For me, one of the most exciting moments of being a game designer is when I hear someone talking about playing one of my games, and they explain a successful tactic for a given situation that I had never considered. This could be a solution to a specific puzzle, a way to incapacitate challenging enemies, or a method for maneuvering a perilous canyon. I see the games I develop as creating situations in which game players can utilize their own creativity to succeed. When the player’s creativity can lead them to solutions, which I had not envisioned, it shows me that my game is doing its job.

Anticipatory versus Complex Systems

Good designers will try to guess what players are going to attempt to do and make their game respond well to those actions. For instance, take an RPG that features a puzzle that involves placing weights on a series of pressure plates. (Having put such a puzzle in a game of my own, I would like to implore game designers to be a bit more creative than that, as pressure plates are surely one of the most overdone puzzle devices still in use. But I digress.) Suppose the designer leaves a conspicuous pile of rocks a few rooms over from the pressure plate puzzle. The obvious solution to the puzzle is to use those rocks on the pressure plates to achieve the desired results. But what if the player tries dropping his various weapons on the plates instead? This is a perfectly valid solution which should work equally well, provided the player has weaponry of the appropriate weights. What if the player has the Summon Minor Threat spell which allows him to summon a variety of different small monsters? If the player summons those monsters onto the pressure plates, they might do the trick too.

Now the designer, having thought through the puzzle fully, can have the programmer add in code where the game reacts correctly if either rocks, weapons, or monsters are on the plates. This is the anticipatory school of game design, where the designer thinks what the player might do and hardwires the game to work well with those actions. I agree that this tactic is surely better than allowing for just one solution. However, what if the player thinks of some other weight he can place on the pressure plates? What if the player uses his Berkshire Blizzard spell on the pressure plates, causing snow to fall on them? Enough snow could conceivably pile up on the plates to have a significant weight. However, if the game has been hardwired only for rocks, weapons, or monsters, the game will not react appropriately. The player will have thought of a perfectly reasonable solution and the game will fail to recognize it.

Instead of hardwiring, however, what if the designer had the programmer come up with a system where every object in the game had a weight associated with it? This would include rocks, weapons, monsters, weather effects, blood, and anything else found in the game-world. If the programmer then made the pressure plates simply get the weight of all of the objects on top of them, regardless of their type, then this one, global solution would work for all objects. If each object was set up with a reasonable weighting, it would not matter what object the player tried to place on the pressure plates, as they would all work automatically.

This latter method is less of an anticipatory system of game design; it is more holistic in its approach. It relies more on creating reliable, consistent systems with which your game will function.

Then, for a puzzle such as the pressure plate one described above, the designer and programmer come up with a series of success conditions for that puzzle. Instead of “the puzzle is solved if the player uses rocks, weapons, or monsters to offset the plates,” the rule is “the puzzle is solved when the plates are offset by the correct weight being placed on top of them.” Certainly, the example of this puzzle is a simple one, but the same techniques can be applied to much more sophisticated and interesting systems which engender a wide variety of successful playing styles.

Emergence

The Civilization games are some of the best examples of complex gameplay emerging out of multiple consistent systems running in parallel. Pictured here: Civilization II.

It is the development of numerous robust and logical systems that leads to player-unique solutions to situations in the game. One could describe these solutions as “emergent” from the systems design of the game, a popular buzzword in game design circles. Establishing a game universe that functions in accordance with logical rules the player can easily understand and use to his advantage allows players to come up with their own solutions to the problems the game presents. Nothing can be more rewarding for the player than when he tries some obtuse, unobvious method for solving a puzzle or a combat situation and it actually works. The more complex systems that work correctly and concurrently with each other, the more interesting and varied the solutions to situations become. Consider the game Civilization, with its numerous systems running in parallel. These systems work together to create some of the most compelling gameplay ever pressed to disk.

Another example of this sort of emergent strategy can be found in the original Centipede. Anyone who has ever played the game knows that the piling up of mushrooms is one of the greatest impediments to a long game, and many players understand the importance of keeping the play-field as clear as possible. As the devotees of the game pumped quarter after quarter into the game, they began to notice some patterns. First, they recognized that the flea is responsible for dropping most of the problematic mushrooms, though destroyed centipede segments also drop them. Second, they saw that the flea does not come out on the game’s first wave. Third, it was observed that the flea is triggered by the absence of mushrooms in the bottom half of the screen. Thus the famous blob strategy was developed, one that the game’s designer, Ed Logg, never anticipated. To use the blob strategy, the player would clear all of the mushrooms from the board on the first wave, and then allow mushrooms to survive only on the bottom-right quadrant of the screen. If, through careful destruction of the centipede, the player only allows mushrooms to be created in that section of the screen, the flea will never come out, making the game much simpler indeed. This is an emergent solution to racking up a high score at Centipede, one which players no doubt felt quite proud of when it was discovered. Furthermore, it was a discovery that Logg, as the game’s creator, did not even know was there to be found. That is good game design.

Non-Linearity

Non-linearity is another buzzword in the game industry, and well it should be. Non-linearity is what interesting gameplay is all about, and many designers forget this in their work. Non-linearity gives interactivity meaning, and without non-linearity, game developers might as well be working on movies instead. The more parts of your game that you can make non-linear, the better your game will be.

In general, when someone says something is linear they mean that it follows a line. A line is a series of points connected in either two- or three-dimensional space, where one can find any point on that line using a specific equation, such as, in a 2D case, y = mx + b. In layman’s terms, this means that a line must be straight. If one considers any two points on that line, say A and B, there is only one way to navigate that line from A to B. There are no choices to be made; one simply must navigate all of the points between A and B. Outside the world of mathematics, we can consider reading a book to be a linear experience. If one is reading a 323-page book and if one does not skip pages or chapters, there is only one way to read the book: by starting on page 1 and reading all of the pages leading up to page 323.

Games, however, are non-linear works. In playing chess, there are multiple ways to capture the opponent’s king, to move from the game’s predetermined starting state to its conclusion. Indeed, there are a vast number of different ways to be victorious in chess, and that variety is what keeps the game interesting. These choices make chess non-linear. Suppose the chessboard were one-dimensional instead of two, each player’s pieces could only move in one direction, and each player had only one piece. This version of chess is a linear one, since there are no meaningful choices for the player to make and the outcome of every game is completely predetermined. And, of course, it is not a whole lot of fun either.

Types of Non-Linearity

So when we say we want our games to be non-linear, we mean we want them to provide choices for the player to make, different paths they can take to get from point A to point B, from the games beginning to its end. We can mean this in a number of ways: in terms of the game’s story, in terms of how the player solves the game’s challenges, in terms of the order in which the player tackles the challenges, and in which challenges the player chooses to engage. All of these components can contribute to making a game non-linear, and the more non-linearity the developer creates, the more unique each player’s experience can be. Furthermore, the different non-linear components can interact with each other to make the whole far greater than the sum of its parts.

Storytelling: I discuss non-linear storytelling in more detail in Chapter 11, “Storytelling.” Of course, a non-linear story line is necessarily tied to non-linear gameplay, and no one would bother to try to make a story non-linear if the game itself offered the player very little in the way of meaningful decisions. Storytelling is perhaps one of the most neglected parts of games in terms of non-linearity, with many developers allowing for non-linear gameplay while constraining their games to a completely linear story.

Multiple Solutions: I discussed above how a well-designed game will enable the player to come up with his own solutions to the challenges the game presents. Not every player will think of the same way to go about solving a situation, and, given that these alternate solutions are reasonable, any challenge must have multiple ways for the player to overcome it. Having multiple solutions to the individual challenges within a game is a big part of non-linearity; it enables the player to have multiple paths to get from point A (being presented with the challenge) and point B (solving the challenge).

Order: Beyond being able to figure out the solutions to challenges in unique ways, players will enjoy the ability to pick the order in which they perform challenges. Many adventure games have made the mistake of being overly linear by allowing the player access to only one puzzle at a given time. In order to even attempt a second puzzle, players must complete the first one. That is a linear way of thinking, which proves especially frustrating when a player gets stuck on a particular puzzle and, due to the game’s linear nature, can do nothing else until that puzzle is solved.

Giving the player choices of different puzzles to solve allows them to put aside a troubling puzzle and go work on another one for a while. After completing the second puzzle, the player may return to the first, refreshed and revitalized, and thereby have a better chance of solving it.

Selection: Another way of making a game non-linear is to allow the player to pick and choose which challenges they want to overcome. Say that between point A and point B in a game there lies a series of three challenges, X, Y, and Z, which are non-order dependent, that is, the player can do these challenges in any order he wishes. What if, once the player surmounts challenge X, he does not have to go back and solve challenge Y or Z, he can simply move on to point B in the game, perhaps never returning to Y or Z? The same is true if the player initially chooses to tackle Y or Z instead of X. Any one of the choices will allow the player to proceed. The advantage is that if the player finds challenge X to be insurmountable, he can try challenge Y or Z. This greatly decreases the chance of the player becoming permanently stuck. It need not be the case that Y is easier than X; the mere fact that it is different may allow the player a better chance of getting through it, depending on his strengths as a player. Other players may find X to be easier than Y or Z, but giving the player a choice of which challenges he takes on allows the player to exploit his own personal skills to get through the game. Of course, after completing challenge X, the player may still have the option of going back and completing the Y and Z challenges, perhaps just for the fun of it or because overcoming those challenges somehow improves his chances down the line. Perhaps completing Y and Z gives his player character greater overall experience or riches. This type of non-linearity can also be used to add totally optional side-quests to the game. These challenges are not strictly required for the player to get to the end of the game, though they may make it somewhat easier or merely provide an interesting diversion along the way. Whatever the case, these optional challenges provide an extra degree of non-linearity, further customizing the player’s experience.

Implementation

Odyssey is an extremely non-linear game, allowing the player to solve puzzles in whatever order he chooses and to select which quests he wants to go on. The game almost always provides more than one solution to any given puzzle.

My first game, Odyssey: The Legend of Nemesis, is without doubt the most relentlessly non-linear game design I have ever done, and includes examples of all the types of non-linearity described above. Odyssey is an RPG and takes place on an archipelago that includes seven primary islands for the player to explore. Though the player is required to complete at least one quest on the first island before moving on to the rest of the game, there are two quests, each with multiple solutions from which the player may choose. Indeed, clever players can skip the quests entirely if they figure out how to rob a particular townsperson. From there, the player is able to move freely about the next five islands, picking which ones he wants to explore and which he prefers to just pass through. Indeed, all that is required for the player to reach the seventh island and the end-game is for the player to successfully navigate each island, killing the monsters that get in his way.

Of course, killing those creatures is made significantly easier if the player receives the rewards for completing the quests. But if the player so chooses, he can skip the entire middle of the game. Of course, few players have done this, preferring instead to explore the different quests and situations they encounter there. Nearly every single one of these quests has multiple ways for the player to solve it, with his actions having a direct impact on how each of the island’s mini-stories resolves. Finally, the game itself has multiple endings for the player to explore, endings which suit the different overall goals the player may have: survival, revenge, or a sort of justice and harmony. Though the game had a very definite story, I am happy to say that I doubt very much that any two players ever experienced it in exactly the same way.

Non-linearity is an extremely powerful tool to use in designing a game, and the descriptions above of the types of non-linearity a designer can employ may seem obvious to the reader. What is astonishing, then, is how many games fail to provide any substantial non-linearity for the player, instead insisting that the player play through the game on a single line from point A to point B.

One reason for this is that creating all of these non-linear elements can be quite time consuming. Consider that between point A and B, we have the aforementioned challenges X, Y, and Z, but the player only has to overcome one of these challenges in order to progress, say challenge X. The player can then continue playing through to the end of the game having never interacted with challenge Y or Z. As a non-linear game, that is the player’s prerogative. The problem arises when a cost accountant looks at the game and tries to figure out where the game’s budget can be trimmed. Well, obviously, if Y and Z are not strictly necessary, why bother having them at all? Why spend a lot of money on the programming, art, and design necessary to get Y and Z working when there’s a chance the player will never see them? Unfortunately, accountants are often not in touch with the finer points of game design, and when you say, “But non-linearity is what makes this game great!” they are likely to dismiss you as “difficult.”

Non-linearity is also often hard to pull off from a design perspective, certainly harder than simple linearity. This may be another reason why so many designers shy away from it at the first opportunity. Designing numerous obstacles that are different enough to provide variety for players while all applying roughly the same challenge is not an easy task. In the X, Y, and Z challenges example, if Z is significantly easier than X or Y, it is quite likely no one will ever bother with X or Y. In a way, a game with poorly designed choices for the player is nearly as linear as a game without any choices at all. The non-linearity your game provides must be meaningful and useful to the player or it is a waste. Designers who think too highly of their own design skills may also avoid non-linearity in their designs because they want the player to experience every single element of the game they decide to include. “Why spend a lot of time on portions of the game that not everyone will see?” say these egotistical designers, starting to sound a lot like the accountants.

The Purpose of Non-Linearity

It is important to always remember that non-linearity is included in the game to provide the player some meaningful authorship in the way she plays the game. If forced to stay on a specific line to get from the beginning of the game to the end, the player will tend to feel trapped and constrained. The challenges along that line may be brilliantly conceived, but if the player has no choice but to take them on in order, one by one, the fun they provide will be greatly decreased.

Non-linearity is great for providing players with a reason to replay the game. Replaying a game where the player has already overcome all of the challenges is not that much fun. In replaying a more non-linear game, however, players will be able to steer away from the challenges they succeeded at the last time they played and instead take on the games other branches. However, it is important to note that replayability is not the main motivation for including non-linearity in your game designs. I have heard some game designers complain that replayability is unnecessary since so many players never manage to finish the games they start playing anyway. So if they never finish, why add replayability? These designers do not realize that the true point of non-linearity is to grant the player a sense of freedom in the game-world, to let each player have a playing experience unique to himself, to tell his own story. If the player wants to replay the game again, that is fine, but the primary goal of non-linearity is to surrender some degree of authorship to the player.

Furthermore, the contention that players seldom finish games and hence the games do not need to be non-linear is a self-fulfilling prophecy. The reason players fail to finish games is often because they become stuck at one particular juncture in the game. This may be a boss-monster who is too difficult, a puzzle that is too confounding, or merely failing to find the exit from a given area. If the game were more non-linear, however, players would have much less chance of getting stuck at any point in the game, since the variety of paths available would increase the likelihood that the player’s unique talents would be sufficient for him to make it successfully past one of them.

At a Game Developers Conference talk entitled “A Grand Unified Game Theory,” Noah Falstein suggested that when non-linearity allows the players to tackle a series of required challenges in whatever order they desire, completing one challenge should make the others easier for the player to accomplish. In the case of a collection of puzzles, this can be done by providing the player with a hint about the other puzzles once he completes one of them. In the case of a collection of battles of some sort, this can be done by providing the player with additional weaponry with which to survive the other battles. Whatever the case may be, using this technique increases the chance that the player will be able to overcome the challenges at hand and get on with the game.

A note of caution: all designers should understand that non-linearity is not about having the player wander around the game-world aimlessly. If the game is non-linear to the point where the player has no idea what she is supposed to try to accomplish or how she might go about it, the non-linearity may have gone too far. Often game designers talk up their in-development games by making statements like “In our game-world, the player can do anything they want; there are no restrictions. The game is completely non-linear!” Such a game would likely be completely annoying as well. Of course, by the time these completely non-linear games have shipped most of the non-linearity has been stripped out and the player is left solving puzzles on a rail. Somewhere between on a rail games and total freedom lies an ideal middle ground, where the player is left with a sense of freedom accompanied by a sense of guidance. （source:gamasutra）