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从游戏开发角度探讨随机性元素的使用

发布时间:2014-11-19 16:43:48 Tags:,,,,

作者:Darran Jamieson

游戏的运气vs技能元素可以说是优秀设计的核心—-这是我们在之前所讨论的内容。但在我们担心如何平衡运气与技能时,我们真正需要问自己的是:什么是机会,在游戏中需要呈现什么程度的机会?此外,我们该如何让以奖励而不是惩罚的形式去执行机会,并使用它去完善整体的游戏体验?

是否需要机会?

我们几乎不可能创造出一款没有运气元素的游戏。没有运气元素的游戏并不算真正的游戏—-这就像是“谁是最高”或“谁拥有最长手指”并未包含任何挑战一样。这是玩家不能改变的最简单的测量方式,并且不可能提供任何娱乐。游戏必须拥有不确定性元素—-就像“谁能够测量出最长的退”,至少这是未事先决定好的事。即使当一名玩家比别人优秀,这也不足以保证他的成功。

我们在许多游戏中使用纸牌,筛子或随机数字生成去创造这种不可预知性。但并非所有游戏都使用了随机工具,像象棋等注重策略的游戏便需要随机元素:这些元素是源自玩家。玩家是不可预知的对象,并且经常会根据自己所预测的最佳结果而改变策略和战术。这便是为何作为一款静态游戏,象棋仍具有很多动态性:因为不存在任何两名玩家会基于同样的方式玩游戏。

人们可以提供机会去玩象棋是因为象棋是非常复杂的,实际上,我们可以将象棋当成是一款复杂的游戏。不幸的是,与“流”或“零和竞赛”理念不同的是,“复杂游戏”这一词并不是一个公认术语。因为我们将频繁地提到复杂这一词,所以我们可以自己对它进行定义。

理解复杂性

一字棋便是一款带有非常简单的规则的游戏。游戏中有9个空间,玩家将操控X或O,尝试着创造一条直线,并且通常移动9次以下便能够结束游戏。我们总是很容易预测一字棋游戏的结果,甚至是在第一次移动之前—-假设两名玩家都准确地玩着游戏,那么游戏有可能是以平局结束。

可以说一字棋并不属于复杂游戏。实际上,我们已经摸清了一字棋的套路,即我们估算出了游戏中每一组可能的移动以及最佳移动组合。更糟糕的是,人们甚至可以无需动用过多脑力便能够“解决”一字棋游戏。

让我们将其与象棋进行比较。象棋带有64个格子并且有6种不同类型的格子,每种类型都有自己的移动组合,并且还包含像王车易位等特殊的移动,这意味着游戏可以永久地持续下去。考虑到这些情况,对于象棋可能是永远都解不开的游戏(甚至当对手是最强大的计算机时)这一点我们一点都不惊讶。

所以从本质上看,复杂游戏是指那些未被解决,或者玩家解决不了的游戏。

“玩家解决不了”这点非常重要。这意味着游戏将持续具有乐趣,因为玩家解决不了其中的谜题。这便是四子连环棋始终受欢迎的原因;尽管计算机能够解开这款游戏,但是玩家却做不到这点。而虽然对于大多数玩家来说一字棋很简单,但对于那些不知道如何规划每一步的孩子来说,它仍算是一款优秀的游戏。所以说复杂性应该是一种主观的看法。

那它到底有何重要性?因为一款不复杂的游戏也就等于一款无聊的游戏。如果游戏一点都不复杂,那么它便很容易解决。如果它被轻松解决了,那么结果便是可预测的;所有玩家需要做的便是计划出最佳移动组合,如此他们便能获胜。这样的话玩家便有可能离开游戏。

边注:我们也可以将一款可被解决的游戏称做一个谜题。尽管谜题很受欢迎,但是直到被解决的时候它才具有乐趣—-这便是为何喜欢字谜游戏的人不会一遍又一遍地坐着解决同一个字谜。决定创造一款益智游戏当然没什么错,但是你必须清楚你的目标是什么,以及这会如何影响游戏的重玩价值。

命运的工具

所以当我们着眼于像象棋或一字棋这样的游戏时,我们可以发现它们都是不具有嵌入式随机性的策略游戏:基本的策略游戏。然而也有许多游戏使用筛子,纸牌或其它工具作为嵌入式机制,如蛇梯棋或扑克。虽然大多数这类型游戏都称不上复杂,但包含筛子或纸牌却是避免游戏轻松被解决的必要元素。在蛇梯棋游戏中,如果玩家每轮中在1至6个格子间选择一个数字进行移动,那么即使是孩子也知道“总是选择6”会是一个最佳策略。

当然了,添加随机性并不意味着能够拯救一款可被解决的游戏。实际上,你可以将目标从“找到解决方法”改成“找到最有可能的解决”。这时候你仍然拥有一款益智游戏,不过获胜条件便没有保证了。太多随机性也不好;蛇梯棋便是一个显著例子。如果只有孩子在玩一款游戏,这便说明游戏缺少任何互动挑战,所以人们会认为这是毫无意义的游戏。

所以为何像扑克这样的游戏能够持续受到欢迎?从根本上来看,扑克是由一系列迷你谜题所组成。你将获得帮助,并需要“解决”这一帮助对于你获胜的可能性。然后你可以根据你获胜的可能性下赌注。

这是对于扑克最简单化的看法,如果这便是这类型游戏的全部的话,它便太无聊了。编写一个程序去评估可能性并运行它去最大化你的获胜机会其实一点都不重要。

扑克的乐趣源自玩家的互动:源自欺骗与自信。你不需要做最好的押注,你也可以往一些没有获胜可能性的内容下赌注。实际上这便是扑克游戏的本质;纸牌只是起到推动作用,并提供全新回合的内容。通过添加随机元素,我们消除了玩家的一些了解,这意味着我们可以使用未知性作为游戏机制。玩家需要基于他们所知道的采取行动,这便是估算获胜几率以及依靠机智战胜其他玩家的结合。

无聊的桥牌

所以,尽管我们谈论的是传统游戏,但计算机游戏也使用了同样的设计原则。像《俄罗斯方块》或《宝石迷阵闪电战》也可以说是带有额外随机性的简单游戏,而像《星际争霸》和《军团要塞》则是复杂游戏。

在几乎所有的游戏中都存在一定的谜题元素。甚至是在RTS或FPS中,玩家也会基于最优游戏玩法不断做出决策:我是应该创建坦克还是飞机?我是应该选择机械枪还是榴弹发射器?我是应该向左还是向右?就像在象棋中,玩家会根据自己的想法是否会创造出最佳结果而做出决定。随机性并不是计算机筛子所创造的,而是由玩家在游戏中所作出的选择所创造的。玩家既尝试着以智取胜,同时也尝试着以技取胜。

实际上,我们可以认为PvP游戏(如FPS或RTS)中的唯一随机元素是来自玩家本身。就像我们之前所讨论的,《军团要塞2》中的暴击是玩家基础的争论焦点—-总的来说,《军团要塞2》中的任何射击都有可能是暴击。暴击需要随机性,而任何由子弹所带来的伤害都会比正常标准强上2,3倍,这便导致暴击成为了致命因子。尽管新玩家喜欢随机杀戮带来的刺激感,但是“持赞成态度的”玩家认为暴击机制对他们的技能是不利的。

我们使用随机数的范围对于结果也具有很大影响。如果步枪每次发射所创造的伤害值是90至110,而我们拥有150个生命值,那么不管发生什么,我们只要被射中两次便会死掉。然而,如果我们拥有100个生命值,那么步枪随机杀死我们的几率便缩减了一半。尽管随机性的范围较小,但使用量却非常重要。

随机性的影响

所以为什么“持赞成态度的”玩家会惋惜暴击系统而“休闲”玩家并不会?答案便是取决于玩家的期待。

持赞成态度的玩家会更频繁地玩自己所选择的游戏。他们会更深入地了解游戏。了解自己受到了什么伤害,能够分配什么,以及任何情景会出现什么结果等等。他们有时候不能有效地做出判断,而这通常是因为低估了对手的技能或者做出了糟糕的瞬间选择。

所以当持赞成态度的玩家进入一场战斗时,如果毫无理由地被子弹击中,他们便会觉得自己上当了。他们知道自己期待发生什么,但是因为随机的筛子滚动,他们很有可能马上就会被杀掉。

而新玩家通常都不会因此而受伤;因为他们不是很了解游戏,也并未期待这可能发生什么,所以他们进入一场战斗后也不一定会期待着自己能够获胜。对于他们来说,战斗只是像技能测试那样的学习经历罢了。

这种被随机性所破坏的期待经常发生于任何带有随机性的游戏中。当你在《俄罗斯方块》中等着直线砖块掉落时,计算机可能会连续给你6个S形砖块,这时候玩家便会觉得自己被骗了。大受欢迎的《Puzzle Quest》便收到许多玩家关于“骗人的AI”的抱怨;其开发者也到各种论坛上解释了它的AI并不是在骗人。

所以为什么玩家会有这种感受呢?为什么玩家会因为随机掉落的宝石颜色而失落?因为随机性颠覆了玩家的期待。当玩家进入一款游戏时,他们期待着能够接受挑战,但他们同时也期待着,只要自己谨慎游戏的话便能获胜。当游戏随机丢给你一些糟糕的数字时,你便会马上失败,然后你就会觉得自己受骗了。你知道游戏是如何进行的,尽管你付出了最大努力,你仍然失败了—-这并不是因为你缺少技能或敌人拥有更棒的策略,而是因为随机性。这对于大多数玩家来说都是非常郁闷的机制。

这种“颠覆玩家的期待”扩展到了各种游戏中。实际上,游戏中的运气元素越多,玩家便越有可能受挫。RPG便是一个显著的例子,特别是因为带有暴击系统。暴击系统经常被当成一个有趣的额外元素,但通常情况下它们也总是会惩罚玩家。这是因为:

1.玩家总是期待着打败大多数敌人。

2.暴击往战斗中添加了随机性。

3.战斗中的随机性意味着不可预知的结果。

4.因此玩家将在他们认为自己可能失败的战斗中获胜,但更常出现的情况是:

5.玩家将会在他们认为会获胜的战斗中失败。

这便是在假设这种遭遇是针对于玩家进行设定的。有些RPG会让玩家面对巨大的怪物并让他们被怪物杀死;然而作为专业的设计师,我们应该确保游戏是针对玩家所定制的,而不是随便丢出几只飞龙便结束。

还有其它问题是(假设我们仔细设计了战斗)暴击系统过分偏向玩家。想象在经历时间和空间的悲痛旅程后,我们游戏的英雄接近了恶魔,随后恶魔不仅摧毁了他飞机还一下子就将其杀死了。这并不是什么传奇之战,这反而会让玩家觉得乏味与不满。玩家想要挑战,而如果游戏因为随机性未能呈现给他们挑战,他们便不可能得到满足。

在《Puzzle Quest》,不管AI是否真的在撒谎其实并不重要:真正重要的是对于有些玩家来说,他们觉得AI在撒谎。玩家不可能忽视运气元素(因为他们期待着获胜),但如果玩家的胜利被一系列不幸的随机元素夺走的话他们便会觉得不公平。

纠正问题

所以我们该如何纠正问题呢?似乎到目前为止我们所说的都是关于“随机性是糟糕的”。从根本来看这并没错。我们是专业的游戏设计师;我们应该随机做某些事。玩家所作出的每个决策都应该是精心设计的游戏体验的结果,而添加随机性有可能会破坏这一点。

当我们更仔细着眼于这一问题时,我们意识到可以基于两大理由去添加随机性:

为了让结果更加不可预测,或者

为了创造内容。

让我们检验这些理由:

不可预测的结果

就像我们之前所提到的,玩家喜欢赢。

而我们在此所说的是随机性稍微取代了我们对于技能的需求。

因此添加随机性将让缺少技能的玩家有可能战胜出色的玩家。而在没有随机性的游戏中,优秀的玩家总是能够赢过缺少技能的玩家。

因为这点,拥有不可预测性可能成为游戏中一大重要组成部分:这让缺少技能的玩家也能够影响游戏,并变得更出色。如果玩家不断遭遇更厉害的对手并不断失败,他们便有可能快速失去对游戏的兴趣。然而,优秀的玩家通常都不喜欢这种随机性,他们认为这是在贬低自己的技能。

所以该如何纠正这一问题?

一个选择便是Elo等级系统。这将给予玩家的技能提高给他们一个数字:如果打败一个最厉害的对手,你的Elo等级将提升;如果输给新手,你的分数便会下降。这是象棋玩家衡量自己的技能的一种方法,但是许多MOBA(游戏邦注:多人在线战斗游戏,如《英雄联盟》和《魔兽争霸》等)也使用了这一方法,所以当你进入一场战斗时,你将面对一些带有相同技能的对手。有些第一人称射击游戏也使用了这一方法,让玩家能够在一方持续被镇压时重新平衡团队。

另外一个选择便是差点系统。这一系统与Elo系统没有太大的区别,它允许玩家能够基于技能级别而提供给自己一个人为优势。打斗游戏便经常使用这种方法,提供给较弱的玩家可变的健康和破坏输出奖励。尽管差点系统可能不能解决所有的技能失衡问题(游戏邦注:因为在线游戏玩家很容易滥用这一系统),但这却能够帮助休闲玩家更平等地与硬核好友们相抗衡。

在这两种情况下,你可以减少内在游戏元素的随机性,并让玩家作为唯一的随机性制造者。

生成内容

随机生成内容(或游戏元素,如《俄罗斯方块》中掉落的砖块)的问题并不是指我们生成的不可预知的内容;而是指随机元素的特定顺序让玩家感到郁闷。

如果在《俄罗斯方块》中,玩家等待的是直线砖块,但是游戏却一直出现S形砖块,玩家便有理由感到厌烦。尽管这是不大可能发生的事,但仍存在发生的几率。

在其它游戏中,如穿越地牢的RPG游戏,我们可能拥有1%的机会在每次怪物出现时生成一个boss。如果我们碰巧连续生成3个boss,那么玩家便会觉得自己身处一个不可能获胜的战斗中。

同样地,我们可能在整款游戏中都不会生成任何boss。这将导致游戏变得非常简单,或者非常复杂(如果boss能够掉落装备升级道具的话)。不管是哪种情况,随机性都有可能破坏玩家在游戏中的乐趣。

在某些特定情况下,随机性可能会将玩家彻底带离游戏。就像在大受欢迎的纸牌收集游戏《万智牌》中,玩家将创建需要结合土地(能量资源)和咒语去打败敌人的桥牌。土地的使用是重要的平衡机制:一个小精灵可能需要一个土地,而一条巨龙可能需要十个土地。然而,如果玩家碰巧没有土地纸牌,他们便什么都做不了;他们只能呆坐在那里直到对手将其打死。尽管我们能在某种程度上缓解这种情况,但这却是一个非常严重的设计缺陷,即玩家在游戏中的多次失败其实是坏运气的结果,而不是因为自己技不如人。

人们的亏损感大大多于成就感。这是一种有趣的心理状况;我们可以着眼于如下两种情境:

你得到1000美元。我问你是否想要将其投注于抛掷货币:如果正面朝上你将再获得1000美元,但如果背面朝上的话你就输了。但不管你选择什么你都能够获得额外的500美元。

你得到2000美元。我问你是否想要将其投注于抛掷货币:背面朝上的话你就输掉了1000美元,但如果正面朝上的话你则不会输钱。不管怎样,你都能够拿回500美元。

一般情况下,人们倾向于选择第一种情况,尽管其结果都是一样的!(不管你是否选择抛掷货币,不管货币是正面朝上还是背面朝上,你最终获得的钱都是一样的。)

这意味着如果游戏中拥有一个随机奖励或惩罚玩家的机制,那么从心理学角度来看,玩家的亏损感会大于成就感。如果这种冒险是可选择的,那便能够开启额外的游戏玩法渠道,但强制性选择总是会让玩家觉得自己在遭受惩罚。

关于随机生成内容的最终问题便是我们很难生成真正有趣的内容。一个典型的例子便是MMO;《魔兽世界》中有无数地牢,每个地牢都需要玩家花费好几个小时的时间进行探险,并需要好几周的时间才可能精通。然而,一旦玩家精通了一个地牢,它们便不再具有多少变量和重玩价值。在《Anarchy Online》中很少有精心设计的地牢:然而,玩家可以进入随机的地牢中。从理论上来看,玩家不会遇到两个完全相同的地牢:然而在实际上,每个地牢给玩家的感觉都差不多。因为地牢是随机的,它们不具有叙述结构或整体的设计理念。比起独特感,每个地牢反而让人觉得都一样。

Spelunky(from xbox)

Spelunky(from xbox)

这些内容可以归结为多少规则正在落实行动以及生成是如何执行的:《Nethack》和《洞穴探险》都使用了随机生成关卡,并拥有强大的用户基础。然而有趣的地图设计的生成规则与随机生成游戏元素是不同的两个问题;我们可以说优秀的设计师应该清楚生成地图的局限性。我们仍然能够在这些地图的生成中使用这些随机讨论内容。

更认真的解决方法

有时候我们会将随机性彻底带离游戏。在RPG游戏中,比起将boss的出现几率设定为1%,我们可以选择让他们出现在玩家进行了100次杀戮后。在纸牌收集游戏中,对抗系统通过将每个可游戏的纸牌设定为土地而不是咒语去解决玩家需要土地的问题;这意味着你永远都不会觉得自己“受困”,并同时能够维持土地所呈现的势头。

然而,彻底删除随机性感觉就像不分精华糟粕全盘将其否定掉一样。在RPG中,让boss在玩家进行100次杀戮后再出现就等于将boss变成是可预测的对象,而当游戏太容易预测时,它就变成了一个谜题。所以更好的选择应该是让boss出现在每50至150次的杀戮后。这意味着boss的出现仍然是基于一个随机的范围内,但这种随机性却不再那么明显。

使用精心控制的数字也是一种伪随机的生成方式。存在许多方法能够做到这点:在《俄罗斯方块》中,如果我们生成了一个L砖块,那么对于接下来的三个砖块我们将“再次滚动筛子”以防止再次出现L砖块。通常情况下,L砖块的出现几率是1/7次,但再次滚动筛子将使它在这三个回合中的出现几率变成1/49。虽然它仍有出现的可能性,但这种可能性被大大缩减了。

当然了,这并非最佳方法:有很多方法能够随机生成数字,从简单的重新掷筛子到加重随机数字;在像《俄罗斯方块》这样的游戏中,留下1/7的机会去生成任何砖块可能会是最佳选择。

如果我们使用了随机性,我们同样也有机会引进seed。这意味着我们在游戏中使用的随机数字并不是真正随机的:“随机”序列是由名为seed的数字所定义的。在《俄罗斯方块》中,它出现在于我们不能预测会掉下怎样的砖块;然而,如果我们赋予《俄罗斯方块》游戏42这个数字,我们便会从方块,L砖块,T砖块,方块开始,然而每一次使用42 seed的游戏都将从这些砖块开始。尽管seed并未经常出现在游戏中(像《我的世界》和《FreeCell》便是两个显著的例子),但却是一个很棒的添加内容。

seed随机性的能力是源自计算机不能真正生成随机数字的事实:通常情况下,它们只能使用一个基数,然后通过计算去获得一个“随机”数字。通过确保基数每次都是相同的,计算将提供给我们同样的“随机”数字。

而关于删除随机性的选择便是为了更多地利用它。这在一开始可能看起来很疯狂,但却是非常有效的:滚动两个筛子,然后将其所得数字加起来,你便拥有1/7的几率去获得7。在这种情况下,通过使用这些随机性几乎就能够彻底删除随机性了。

结论

最后,我想说的是随机性并不是什么邪恶的内容;它归结起来就是一种感知。玩家想要接受挑战,或者拥有有趣的体验,但是丢给玩家一群随机的怪物既没有挑战也不有趣,且与他们是死是活也没多大关系。不管通过缓解随机性,我们可以创造出想要的结果,并创造出能够与玩家互动而不是忽视他们的游戏。

关于随机性的最后几点注意事项

随机性通常是解决冲突的一种糟糕方式,因为它会创造出不可预知的结果。随机性也是生成内容的一种糟糕方式,但它通常也是这么做的唯一明智的方式;就像设计一款《俄罗斯方块》般的游戏,我们就需要拥有一列关于每个砖块的掉落的列表。

当随机性出现时,它通常都是为了迎合玩家的洗好。如果游戏元素是随机生成的,它们将允许玩家能够对最糟糕的情况作出反应,但同时仍提供给他们合理的成功几率。

然而,我们必须接受有时候随机性也是必要的这一事实。如果没有随机性去决定战斗的话,RPG也就不再那么有趣了。特别是桌面游戏更不可能快速解决问题:对于蛇梯棋这类型游戏来说,丢1000次筛子并得出平均数是不现实的。

最后我必须强调的是:如果你彻底删除了随机性,那么你创造出来的可能就不是一款游戏,而是一个谜题。

本文为游戏邦/gamerboom.com编译,拒绝任何不保留版权的转功,如需转载请联系:游戏邦

A Look at Luck in Game Design

by Darran Jamieson

The luck vs. skill aspect of games is one which is fairly central to good design—indeed, it’s something we’ve covered before. But before we worry about trying to balance luck and skill, we really need to ask: what is chance, and to what extent is it necessary in a game? Furthermore, how can we implement chance in a way that feels rewarding rather than punishing, and use it to improve rather than detract from the overall playing experience?

Is Chance Required?

It’s nearly impossible to create a game without luck. A game without luck isn’t really a game—something like “who’s the tallest” or “who has the most fingers” doesn’t really involve any sort of challenge. These are simply measurements that the players are unable to change, and so are unlikely to provide much entertainment. A game must have an element of uncertainty—something like “who can balance on one leg the longest”, while not terribly in depth, is at least not predetermined. Even when one player is better, their success is not always guaranteed.

For many games, we use cards, dice, or a random number generator to create this unpredictability. But not all games use randomisation tools, and a serious strategy game like chess still requires an element of randomness: this element comes from the players themselves. Players are unpredictable, and will often adjust strategies and tactics on the fly, based on what they consider the best probable outcome. This is why, despite being a fairly static game, chess games can vary wildly: no two players approach the game the same way.

The reason humans can provide chance to chess is because chess is incredibly complex – in fact, we can describe chess as a complex game. Unfortuntely, unlike concepts such as “flow” or “zero sum game”, the term “complex game” isn’t a recognised term. Since we’ll be talking about complexity a lot, we should probably define what we mean by it.

Understanding Complexity

So what is a complex game?

If we look at Tic-tac-toe, we can see a game with fairly simple rules. There are nine spaces, players place an X or an O, trying to make a straight line, and the game is always over in nine moves or fewer. It’s fairly easy to predict the results of a Tic-tac-toe game, even before the first move is made—assuming the two players play “correctly”, then the game will always end in a draw.

We can say then, that tic-tac-toe is hard to justify as a complex game. In fact, Tic-tac-toe has been solved, which is to say that we’ve calculated every set of possible moves, and essentially proven the best moveset. To make matters worse, humans are capable of “solving” a tic-tac-toe game without much mental agility.

Compare this to chess, which has 64 pieces and six different types of piece, each with their own moveset, special moves such as castling and en parssant, and a ruleset that means a game could (technically) last forever. Given these conditions, it’s perhaps unsurprising that chess has never been solved, even by the most powerful computers.

So, essentially, a complex game is one which has not been solved, or that cannot be solved by the players.

This addendum “cannot be solved by the players” is important. It means that games can continue to be fun, assuming the players are incapable of solving them. This is why Four-in-a-row (also known as Connect 4) remains a fairly popular game; although computers have solved it, when players sit down they are unlikely to be capable of calculating the perfect game in their heads, so they play non-optimally. Tic-tac-toe, while trivial for most players, is still a good game for young children who are unable to plot out every move in their head. Complexity is subjective.

So why is this important? Because a non-complex game (a simple game) is a boring game. If the game is not complex, then it is solvable. If it is solvable, then the outcome is predetermined; all the player is required to do is work out the best moveset, and they’ve won. And at that point, they may as well go back to playing “who has the most fingers”.

A small sidenote here, a solvable game can be better described as a puzzle. And while puzzles are popular (many newspaper print daily crossword puzzles), a puzzle is only fun up until it’s been solved – which is why crossword enthusiasts generally don’t sit and solve the same crossword over and over. Theres certainly nothing wrong in deciding to make a puzzle game, but be aware of what it is you’re aiming for, and how that will impact replayability.

Tools of Fate

So, when we look at games like chess or Tic-tac-toe, we can see they are all strategy games with no inbuilt randomisation: basic strategy games. There are, however, many games which do use dice, cards or other tools as an inbuilt mechanic, like snakes and ladders or poker. As most of these games can’t be considered complex, the inclusion of these dice or cards is necessary to prevent the game from being solvable. If, in the game of Snakes and Ladders, rather than rolling, players chose a number between one and six spaces to move every turn, then even children would quickly work out that “always choose six unless you land on a snake” is an optimal strategy.

Of course, adding randomness does not automatically make a solvable game good. In fact, you simply change the aim from “find the solution” to “find the best probable outcome”. You still essentially have a puzzle game, except that the win condition is not guaranteed. Too much randomness is just as bad as none; here again Snakes and Ladders is an obvious example. Almost no-one other than children plays the game, as it lacks any sort of interactive challenge and, therefore, people see it as ultimately pointless.

So why does a game like poker continue to work? Poker is, essentially, a series of mini puzzles. You are given a hand, and you have to “solve” how probable it is for you to win. You can then bet on your hand, based on how likely you are to win the game.

This is an oversimplified view of poker, and if this was all there was to the game, it would be fairly boring. It would be trivial to write a program to calculate the odds (although people do that anyway), and simply run it to maximise your wins.

The fun of poker comes from player interaction: from bluffing and confidence. You are not required to bet on a good hand, and you are able to bet on junk. In fact, this is arguably what the game of poker is truly about; the cards are simply there to facilitate this, and to provide a fresh round of lying every few minutes. By adding the random element, we’ve eliminated player knowledge, which means that we can use uncertainty as a game mechanic. Players are required to perform based on what they know, and it is the combination of calculating winning odds and outfoxing other players that lets poker maintain its fanbase.

Bored of Boards

So, although we’ve been talking about about traditional gaming, computer games use exactly the same principles of design. Games like Tetris or Bejewelled can be considered simple (with added randomness), and games like Starcraft or Team Fortress can be considered complex.

In almost all games, there is a certain puzzle-like quality. Even in an RTS or FPS, players are constantly making decisions based on optimal play: should I build tanks or planes? Should I choose the machine gun or grenade launcher? Should I turn left or right? Like in chess, the player attempts to make decisions based on what they think will result in the best outcome. The randomness isn’t (generally) provided by computer dice, but by the choices of the players in the game. Players are trying to outwit each other, as well as outskill them.

In fact, its possible to argue that the only randomness in a PvP game (like an FPS or RTS) should come from the players themselves. As we’ve talked about before, crits in TF2 are a subject of much contention in the playerbase—to summarise, any shot in TF2 has the possibility of being a crit shot. Crit shots require nothing more than the roll of a dice, and any damage dealt by a critical bullet will be twice or three times as much normal, which causes crits to be frequently lethal. While new players may enjoy the thrill of randomly getting a kill, “pro” players will see the crit mechanic as unnecessarily spoiling their skills.

The range of numbers we use for randomness also play a large effect on how things pan out. If a rifle deals 90-110 damage a shot, then if we have 150 health the random element is really a flavour effect: no matter what happens, we need to be shot twice to die. However, if we have 100 health, than a rifle will randomly kill us in one shot half of the time. Despite there only being a small range in randomness, the numbers used matter a great deal.

The Effects of Randomness

So why is it that “pro” players bemoan crit systems (and improperly implemented damage ranges) whereas “casual” players don’t? The answer, simply, is player expectation.

A pro player will have played their game of choice a lot. They will know it inside and out. They will know what damage they can take, what they can deal out, and what the outcome of any situation should be. And while they may sometimes judge things poorly, it is generally due to underestimating the opponent’s skill level, or making bad split-second decisions.

So when a pro player enters a battle, and they are instantly gibbed by a bullet for no reason other than luck, they might feel cheated. They knew what they wanted to happen, but because of an electronic dice roll, they were instantly killed instead.

New players will generally not feel this sting as sharply; they don’t know the game as well, they have fewer expectations of what should happen, and so they can enter a battle not really expecting to win. To them, battles are as much a learning experience as a test of skill.

This randomisation destroying expectation is something that can happen in almost any game with randomness. When you’re waiting for a line block in Tetris, and the computer instead gives you six S blocks in a row, the player might feel a little cheated. The popular game Puzzle Quest (essentially a bejewelled clone with RPG elements) received many player complaints about “cheating AI”; there are enough forum threads about it that the developers had to specifically come out and say that the AI doesn’t cheat.

So why does it feel this way? Why are so many players upset over randomly falling jewel colours? Because the randomness is subverting player expectations. When a player goes into a game, they are (generally) expecting to be challenged, but they’re also expecting that if they play well, they can win. When the game randomly throws some bad numbers at you, and you immediately lose, then you can feel cheated. You had an idea of how the game was going to play, and despite your best efforts, you were defeated—not by your own lack of skill, or superior opponent strategy, but by electronic dice. This, for most players, is incredibly infuriating.

This “luck subverting player expectation” extends into all sorts of game. In fact, the more luck involved in a game, the more likely it is to be frustrating. RPGs are a notable example, especially because of crit systems. Crits systems often seem like a fun little addition, but by the numbers they will almost always punish the players. This is because:

1.Players are, generally, expected to defeat most enemies.

2.Crits add randomness to battles.

3.Randomness in battle means unpredictable results.

4.Therefore, players will (occasionally) win battles they should have lost, but more often:

5.Players will lose battles they should have won.

This is, of course, assuming that the encounters are designed or tailored towards the player. Some RPGs simply throw the player at giant monster and be done with it; however, as professional designers, we should be looking to ensure that the game is tailored towards our players, rather than just throwing some dragons in and calling it a day.

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The other problem then, assuming we have designed our combats carefully, is that a crit system over-favours the player. Imagine if, after a harrowing journey through time and space, the hero of our game walks up to the ancient demon terrorising the planet and kills him in one (critical) blow. Its not quite the epic battle of legend, and is likely to leave the player feeling underwhelmed and unsatisfied. A player wants a challenge, and denying them that challenge because of randomness is unlikely to provide satisfaction.

In the case of Puzzle Quest, whether or not the AI actually was cheating isn’t actually important: what is important is that to some players, it felt like the AI was cheating. The lucky streaks gotten by the player are likely to be ignored (due to their expectation of winning anyway), but having your victory snatched away by a series of unfortunate dice rolls may seem unfair and punishing.

Fixing Things

So how do we fix things? It might seem like so far all we’ve really said is “randomness is bad”. And essentially, that’s true. We’re professional games designers; we shouldn’t be doing things randomly. Every decision the player makes should be the result of a carefully crafted experience, and putting in randomness can endanger that.

When we look more closely at it, we realise that randomness can be added for two primary reasons:

To make the outcome unpredictable, or

to generate content.

Let’s examine these:

Unpredictable Outcomes

As we talked about in our previous article, players enjoy winning.

As we talked about here, randomness somewhat replaces the need for skill.

Therefore, adding randomness to a game allows (in some sense) bad players to win against good players. In a game with no randomness, a good player will always win against a bad player.

Because of this, having this unpredictability can be an important part of a game: it allows bad players to influence the game, and (hopefully) become better. If a player is constantly matched up against superior opponents and is losing, chances are they will quickly lose interest.
However, good players will often dislike this randomness, and will often be put off by a game which “punishes” their skill.

So how can we fix this?

Well, one option is to have an Elo rating system. This essentially gives players a number based on their skill level: beat a grandmaster, and your Elo rating goes up; lose games to newbies, and your score will probably go down. It originated as a way for chess players to measure their skill, but many MOBAs (Multiplayer Online Battle Arenas, such as League of Legends and Defense of the Ancients) do this, so that when you enter a battle you are (theoretically) placed with people around the same skill level. Some first-person shooters have also attempted this, allowing players to rebalance the teams if one side is continually getting crushed.

Another option would be to have a handicap system. Not too dissimilar to an Elo system, a handicap system allows players to give themselves an artificial advantage based on their skill level. Fighting games will often do this, giving the weaker player a variable health and damage output bonus. Although a handicap system might not solve all skill imbalance issues (it’s easy to imagine online players abusing a system like this), it’s a good way to allow casual players to compete more equally with their hardcore friends.

In both these cases, you can reduce the randomness of innate game elements, leaving the players as the only randomness generators.

Generating Content

The problem with generating content randomly (or gameplay elements, like in the game of Tetris’s falling blocks) isn’t so much that we’re generating unpredictable content; it’s that, often, certain sequences of random elements are extremely punishing to the player.

If, in Tetris, the player is waiting for a line block, but we only generate S blocks for the rest of the game, then the player will have every right to be annoyed. And, while it’s improbable, it can happen.

In other games, such as a dungeon crawl RPG, we might have a 1% chance of generating a boss every time a monster spawns. If, by chance, we generate three bosses in a row, then the player might find themselves in an unwinnable battle.

By the same token, we might go through the game and never generate a boss. This could make the game incredibly easy, or (if the bosses drop equipment upgrades) incredibly hard. In either case, randomness has essentially destroyed our players’ enjoyment of the game.

In certain cases, randomness can completely remove a player from the game. In the popular collectible card game Magic: The Gathering, players build decks that require a combination of lands (power sources) and spells to defeat their opponents. The use of lands is an important balancing mechanism: a simple goblin might require one land in play, while a mighty dragon might require ten. However, if the player happens to draw no land cards, then they are unable to play anything; they are essentially forced to sit there with zero options until their opponent defeats them. While it’s possible to mitigate this to some extent, it’s a serious design flaw that a non-insignificant number of game losses are the result of bad luck, rather than being outplayed.

People feel loss more strongly than they feel gain. It’s an interesting psychological phenomenon; consider these two scenarios:

You are given $1,000. I ask if you want to gamble on a coin toss: heads you win an extra $1,000, tails you don’t. Alternatively, you can just have an extra $500 (no coin toss required).

You are given $2,000. I ask if you want to gamble on a coin toss: tails you lose $1,000, heads you don’t. Alternatively, you can just give back $500 (no coin toss required).
In general, people tend to take the guaranteed extra $500 in the first case, but gamble on the coin toss in the second… even though the outcomes for gambling are the same in each scenario! (Do the maths: whether you choose to flip the coin or not, and whether the coin comes up heads or not, the amount of money you end up with in the end is the same regardless of whether we’re talking about Option 1 or Option 2.)

This means that, if you have a mechanic in game which randomly rewards or punishes they players, the losses will, psychologically, outweigh the gains. If the gamble is optional then it opens up extra avenues of gameplay, but a forced gamble will mostly feel like punishment.

A final problem with generating content randomly is that it can be very difficult to generate content which is interesting. A great example of this is MMOs; World of Warcraft has dozens upon dozens of dungeons, each of which can take hours to complete, and weeks to successfully master. However, once the dungeons are mastered, they (arguably) offer few variations and little replayability, save for the obvious grind for equipment. In Anarchy Online, the number of designed dungeons was tiny: however, players could enter randomised dungeons. In theory, no two dungeons the players encountered would ever be the same: however, in practise, every dungeon felt the same. Because dungeons were randomised, they had no narrative structure or overall design concept. Instead of feeling unique, every dungeon felt the same.

A lot of this is down to how many rules are put in place and how the generation is implemented: Nethack and Spelunky both use randomly generated levels, and have massive fan bases. The generation of rules for interesting map design is, however, a slightly different issue from randomly generating gameplay elements, and is probably best left for another discussion; it suffices to say that a good designer should be aware of the limitations of generating maps. We can still apply much of this randomness discussion to the generation of these maps, however.

A More Serious Solution

So where does this leave us? Well, sometimes we can actually just remove randomness from a game entirely. In the case of an RPG, instead of spawning a boss 1% of a time, we can spawn them after every 100 kills. In the case of collectible card games, one of Magic’s competitors (Versus system) solved the issue of players needing land by making every card playable, face-down, as a land instead of a spell; this meant that you would never find yourself “stuck”, while maintaining the momentum that lands crucially provided.

However, a total removal of randomness can often be an overzealous case of throwing the baby out with the bath water. In the example of the RPG, making a boss spawn every 100 kills exactly is likely to make them too predictable, and when a game gets too predictable, it becomes a puzzle. A better option would be making a boss spawn somewhere between every 50 and 150 kills. This means that bosses are still within a random range (making them hard to predict), but aren’t so random you can get attacked by three at once.

This use of carefully controlled numbers is pseudorandom generation. There are many ways to do it: in Tetris, if we spawn an L block, then for the next three blocks we “re-roll the dice” once if an L block is spawned again. Normally, the L block has a one-in-seven chance of spawning, but giving it a re-roll makes it a 1/49 chance for those threee turns. It can still happen, but is much less likely.

This isn’t the best way, of course: there are many ways to generate numbers randomly, ranging from simple re-rolls to weighted random numbers; plus, sometimes, in a case like Tetris, just leaving it as a one-in-seven chance to generate any block might be the best option.

If we do use randomness, we also have the opportunity to introduce seeds. This simply means that the random numbers we use in our game aren’t actually random; the “random” sequence is entirely defined by a number called a seed. In Tetris, it appears that we can’t predict what blocks are going to fall; however, if we seed a tetris game with the number 42, and we start off with square, L block, T block, square, then every game that uses the 42 seed will begin with those blocks. Seeds aren’t used often in gaming (Minecraft and FreeCell being two notable examples), but can be a nice addition.

The ability to seed randomness comes from the fact that computers aren’t actually capable of generating random numbers: often, they simply take a base number (such as the time in milliseconds), and then perform a calculation to get a “random” number. By ensuring the base number is the same every time, the calculations will give us the same “random” numbers.

The alternative to removing randomness is to use more of it. This might seem crazy initially, but can actually be extremely effective: roll two dice, add them together, and you have a one in six chance of getting a seven. Roll 2,000 dice, add them together, divide by 1,000 (and round), and you will almost always get a seven. In this case, using so much randomness has almost entirely removed randomness.

Summing Up

At the end of the day, randomness isn’t inherently evil; it all comes down to perception. Players want to be be challenged, or to have an interesting experience, and there’s nothing challenging or interesting about throwing a bunch of random monsters at a player, with little regard to whether they live or die. By tempering the randomness, we can craft the results we want, and hopefully make a game which interacts with the player, rather than ignoring them.

A Few Final Notes About Randomness

Randomness is generally a bad way to solve conflict, because (by its very nature) it creates unpredictable results. Randomness can also be a poor way to generate content, but is often the only sensible way to approach it; imagine designing a Tetris game which had a list of every block that should drop, in order.

When randomness does occur, it should generally favour the player (which is hard to achieve in a player vs player environment). If game elements are generated randomly, they should allow the player to react to a worst case scenario in a way that still allows a reasonable chance of success.

However, we have to accept that sometimes randomness is necessary. RPGs would be a lot less exciting without dice to determine combat. Board games, in particular, are unlikely to resolve the issue anytime soon: throwing 1,000 dice and averaging out just isn’t practical for a game of Snakes and Ladders.

And of course, the final big caveat: if we remove randomness entirely, are we making a game, or a puzzle?(source:tutsplus)

 


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