作者：Julian Pritchard

我刚刚设计好一款卡片游戏；我为此很得意：游戏的规则非常巧妙，玩家可以在游戏中尝试各种策略。我把规则解释给两个朋友后，他们就开始试玩。我期待着看他们吃惊的表情。

然而，结果是我吃惊了：其中一人居然靠使小把戏赢了，因为我的游戏很不幸地存在漏洞。

发现漏洞后，这款游戏与我原来的设计就不一样了。最终，我决定把这款卡片游戏改成桌面游戏，这样就可以保持我原来的想法，同时去掉漏洞。

调整游戏后，我对从游戏中发现的漏洞产生了浓厚的兴趣。我开始研究它们如何影响游戏。在本文中，我将对我的研究作一番总结，内容包括漏洞的定义、破坏性和类型。本文还将附上修补这些漏洞的方法。

漏洞是什么？

如果某样东西可以被滥用，那么它就会被滥用。 ——Hyrop的“漏洞法则”

漏洞可以定义为，系统中的缺陷，玩家可以通过它得到有失公平的或意想不到的优势。——Fullerton，《游戏设计工作坊》

漏洞通常是在自生性游戏性中产生的：即当两个或以上的游戏机制、规则共同起作用时，产生了一些意料之外的结果。当游戏规则不能完全限制或强制合法行为时，漏洞就产生了。

当玩家非常熟悉游戏规则时，或者在偶然的情况下，玩家会发现漏洞。无论玩家在什么情况下发现漏洞，结果总是一样的：他们会利用漏洞，无论能否让游戏变得更有趣。玩家利用漏洞而不是享受游戏乐趣的典型例子就是，刷成就。

漏洞导致不合理的玩家行为。在下文中，我将论述玩家利用漏洞可能做的、但设计师（通常）不希望看到的事。

相关概念

漏洞成为玩游戏的退化策略。在所有可以使用的策略中，使用优势策略是最可能获得成功的。所谓的“退化策略”就是指总是产生成功的优势策略（游戏邦注：并非所有优势策略都是退化策略：“囚徒困境”就是一个经典的例子）。

漏洞通常是bug，但只有能被玩家利用的bug才会成为漏洞。

许多漏洞的结果是破坏秩序（也就是，玩家利用漏洞体验正常秩序不允许的事件），但只有能让玩家获得好处的秩序破坏才是漏洞。

玩家利用漏洞的行为有违游戏精神。但并非所有有违游戏精神的行为都是漏洞导致的。例如，有些行为需要借助特殊的工具破解了游戏才能完成。这类行为通常属于作弊。

漏洞的案例

在《Bastion》中，玩家可以故意从驳船上掉下来，使游戏在非战斗状态时在移动的驳船上强制重刷玩家。通过这种做法，玩家可以跳过部分关卡，不必展开战斗。这个漏洞的第二个效果就是，叙述者没有意识到发生了什么事；他会兴高采烈地继续谈战斗，以为战斗仍然在进行。

在更早版本的《Desktop Dungeons》中，每个地下城有三个神坛。每个神坛会从9个神中随机解锁1个神。这些神通过任务会逐一解锁。玩家发现，如果他们只解锁了3个神，就可以很肯定哪三个神会刷出来。这样，神的随机性就消失了。开发者的解决办法是，在每个地下城只放一个祭坛，直到玩家解锁完4个神。

在《世纪之石》中，有可能会出现石头砸到门，然后在通道上反弹的情况。在这之后，石头会回到通道上，这样玩家只跑一次路线就可以砸门两次了。这是一个很有害的漏洞，因为游戏要求玩家在砸开门以前必须在通道上往返。

在万智牌《魔法风云会》的游戏过程中，卡片可以消掉它下面的任何一张卡片。有些玩家会把卡片撕开，散放到对手的卡片组中，这样就可以消掉多张卡片。当玩家第一次这么做时，裁判会将其判定为合法，因为并没有规则要求不能将卡片撕开。

在《辐射3》中有一个漏洞，也就是，玩家可以直接前往城市The Citadel，然后使用任何道具跳进这个城市，这样就跳过了游戏中的很大一部分，不必完成任务。

在《上古卷轴5：天际》中，玩家可以把桶放在NPC的头上，然后打劫他，这样NPC就不会发现了。

在《骇客任务》中，玩家可以把LAM手榴弹当作感应地雷或者梯子，这样玩家就以不合理的方式进入区域了。

一个10岁的骇客公布了《核战危机》中的漏洞：在这款运行在手机设备上的社交游戏中，你可以把时间调前，这样就可以提早收到奖励了。

除了以上案例，《文明4》、《天际》、《模拟人生3》等都存在漏洞。

漏洞的破坏性

根据Adams所述，游戏玩法是：

1、玩家在实现游戏中的目标以前必须面对的挑战

2、玩家应对这些挑战时允许采取的行动

漏洞对这两方面都构成危害。

漏洞消除了游戏的挑战性。正如前面提到的，玩家总是选择最简单的方法达到目标。漏洞相当于开了一条新捷径，有效地消除了开发者在游戏中设置的挑战。没有挑战性，游戏玩法也就毁了。

漏洞消除了有意义的选择。漏洞破坏游戏的平衡性，不平衡的选择总是不怎么需要动脑的。漏洞的存在减少了玩家可以采取的有意义行动。

漏洞为什么不好？还有另外两个原因。

漏洞消除了多人游戏中的公平性。不公平的游戏是不可能好玩的，因为所有玩家都会靠漏洞保持自己的竞争力。设计师应试始终保持游戏的公平性。

漏洞破坏了“第四堵墙”（游戏邦注：这里的“第四堵墙”借用了戏剧中的术语；在戏剧中，写实场景的室内只有三面墙，而面向观众的一面则被视为假想的“第四堵墙”。它的作用是将演员与观众隔开，使演员忽略观众的存在）。当玩家利用漏洞时，游戏的反应就会暴露它的局限性和潜层机制。这就消除了游戏中的真实感，因为没有了魔法光环，游戏中的氛围和剧情都不再合理了。前文中提到的《Bastion》叙述者失效就是一个典型的例子。

漏洞的一般类型

以下行为可以发生在任何类型的游戏中。它们是许多游戏的玩法，但是，当设计师并不意图这些玩法的出现的时候，它们就变成了漏洞。

避免玩家记忆游戏事件的最简单的办法就是引入随机元素，可以是随机AI行为、随机道具、随机AI位置或者甚至随机AI时限。

所谓的预测就是，玩家学习AI的逻辑，然后估计它的下一步举动，从而轻松地打败它。

正如前面所说的，随机元素可以避免玩家的预测行为，或使AI显得更精巧（本质上说，是更加依赖多次的输入变量）。

“蛮干”（也叫作“变换玩法”）是一种解决某类益智题的办法。当玩家必须想出正确的移动、数字、按钮等组合时，往往会使用“蛮干”（例如，在《机械迷城》中有许多这类益智题）。

在某些情况下，蛮干就是解决问题的方案。但是当设计师意图玩家靠游戏提供的逻辑和线索解决益智题时，蛮干就是一种漏洞了。

解决办法就两种：

1、增加更多组合（例如，再增加一个影响益智题的元素，从而使可能的解决方案数量翻倍），这样蛮干的策略就会显得不实用了。

2、使逻辑和线索更加明显。

在点击类冒险游戏中，“象素搜索”是一种特殊形式的蛮干，也就是玩家的鼠标在整个屏幕上随便悬浮（或点击），直到弹出提示告之玩家可操作的点。

当鼠标悬浮在可操作点上时，或点击到可操作点时，可操作点就会被突出——玩家在任何有这类机制的游戏都可能使用象素搜索，例如，在FPS中，当十字标经过隐藏的敌人时，它就会变红。

在某些情况下，游戏的意图就是让玩家搜索象素，如《质量效应2》中的资源扫描。

“误导”是指玩家故意以低于实际水平的方式玩游戏，使游戏的动态难度调整机制降低游戏难度。这种做法使游戏变得更容易，最终导致玩家轻松获胜（游戏邦注：这类似于现实世界中的撞球比赛，高手故意隐藏真实水平，使对手放松警惕）。

误导经常出现在单人模式的赛车游戏中。赛车游戏使用动态难度调整机制，其作用是根据玩家的水平调整AI赛车的水平：玩家越快，AI也越快。在赛车游戏中，玩家的误导做法就是故意保持第二名（即使他可以超过第一辆赛车），直到最后一圈再猛冲。只要玩家保持第二名，游戏就不会提高难度，因为游戏以为玩家已经受到挑战了。

要解决误导问题可能很困难。赛车游戏《Pure》使用了一种复杂的解决办法。游戏一开始，它的系统就会动态地设置跑在玩家前面一段距离的AI。这意味着玩家在整个赛车过程中，始终与AI势均力敌，这样他想靠最后一圈的冲刺赢AI就不太可能了。但与这种AI比赛，玩家通常能够取胜，只是不太可能误导游戏了。

“碰运气”通常出现在随机关卡生成的游戏中。玩家先大致看一下关卡，再决定是否能够通关；如果不能，他就会重开关卡，等游戏生成更有可能通过的关卡。与误导类似，碰运气的玩家玩到的游戏难度比游戏设计师所期望的低。

以下方法可以防止玩家碰运气：

1、标准化关卡难度，这样随机生成的关卡难度都差不多（这个方法有难度，需要深入理解数值和游戏机制）。

2、禁止新关卡生成，除非玩家已经玩了之前生成的关卡。这要求设计师保证所有关卡是公平的。这个办法的风险是，如果玩家无法通关，可能会永远离开游戏。

3、使玩家更难判断关卡难度，也就是说，当玩家意识到关卡的难度时，他在这一关所花的时间已经足够他打消退出的想法了。

FPS中的漏洞

“擦边式”是指玩家站在角落射击部分敌人，而敌人看不到玩家。这个漏洞可以通过让AI敌人寻找伤害的来源解决。

“突击式”与“擦边”类似，不同的是，玩家从角落里突然现身，打几枪又躲回角落。与“擦边式”的解决办法一样，让AI敌人逼近玩家攻击。

“楔入式”可以用来对付射程短的敌人：玩家把敌人困在一个它无法攻击到玩家的地方，这样玩家就可以很轻松地打它了。

解决这个漏洞的办法是，修改关卡设计或改进AI，给敌人更远的射程，使它能接近玩家；或者做一个东西把玩家拉近敌人（例如使用绳子）。

“隔空式”是指当玩家移动得比敌人更快或射击得比敌人更远时，他可以一边倒退一边攻击敌人，而自己不受伤害。

“驻扎式”是指玩家驻扎在一个敌人看不到他的地方，然后从那个地方攻击敌人。驻扎通常需要一定的距离，并且使用狙击武器。

简单地让敌人回击可能会让玩家觉得受骗了。更好的解决方法是，让敌人朝玩家移动。另一个方法（在多人游戏中特别管用）是精心设计关卡，不留任何适合驻扎的地方，或者给予其中一方以足够的反馈手段，使其获知另一方的驻扎位置；例如，《现代战争2》中的心跳传感器、无人机和KillCam。

“驻扎改良式”与“驻扎式”类似。玩家站在离敌人较远的地方，然后朝会对敌人造成范围伤害的物品射击，如射中手榴弹。

这个问题的解决办法有两个：第一，根据一点物理数学的计算，使AI可以避开接近中的投射物产生的范围伤害；第二，AI可以找出发起攻击的玩家。

“顺序式”是指玩家从敌群中挑选敌人，逐个击破。这往往发生在狭窄的空间中，或者当敌人从群体中分散出来时。如果设计师的意图是让玩家难以战胜集体式攻击，而玩家现在却能选择先打掉哪个敌人，那么这就成了一个漏洞。

最简单的解决办法就是，在周围的敌人中触发警戒状态，使他们集体朝玩家移动。另外，为了防止“顺序式”，战斗空间也要认真设计。

多人游戏中的漏洞

“龟缩”通常发生在有资源系统的游戏中——往往是战略游戏，并且玩家超过2人。当两方玩家交战时，双方都会消耗资源。这就使参战双方处于不利地位，因为他们在战斗时都损失了资源。而同时，采取“龟缩”战术的一方却比双方更好过，因为他在之前的战斗中没有消耗资源，这就使他在下一场战斗时比另外两方更有优势。

这个漏洞的后果就是，游戏中的所有玩家都选择当“乌龟”，这当然就阻碍了游戏的发展。解决办法是，奖励战胜方，并且奖励足够弥补战斗造成的损失。

“弑君”通常出现在玩的过程中显示排名的游戏中。玩家往往结成同盟一起攻击领导者，因为他是最可能获胜的人。

简单的解决办法是，取消游戏过程中的排行榜。更复杂的解决办法是防止玩家与其他玩家合作。

“沙包”是应对“弑君”产生的。优秀的玩家知道其他人可能会进攻自己，如果表现得太突出的话。为了防止这种情况，他会故意隐藏自己的实际水平，直到时机成熟时再一举获胜。注意，“沙包”通常发生在能动态调节难度的游戏中。

解决办法与“弑君”一样：移除排行榜。如果玩家不知道谁最强，就没理由采取“沙包”战术了。

“外交”是指得分低的玩家虽然不能赢，但他的行动可能决定哪个优势玩家能胜出。这些行动可以是给其他玩家赠送资源、或合并军队。这就把外交元素引入游戏了，也就是玩家可以通过建立关系获胜，而不是技术（如果这不是游戏设计的意图，那么就是漏洞了）。

解决办法与前面两种一样：移除排行榜。

“混水”的形式多样，但基本形式一样：当一伙玩家合力达成一个目标时，“混水”的玩家只参与，不投入。

在经验由最后一击的玩家获得的游戏中，混水者在战斗中表现低调，只等最后一击杀掉敌人拿经验，这种做法的死亡风险几乎为零。

在经验根据是否在杀敌范围内分配时，混水者可以一直保持被动，虽然得分落后，但不承担风险就能获得经验。

“混级”是一种特殊的“混水战术”：一伙玩家由一个高级玩家带领杀高级的敌人。因为级别上的跨度，低级玩家会得到大量经验，使升级更快。

简单的解决办法是把经验经分给伤害输出最出的玩家，或让所得经验与伤害输出成正比。

“纯混”是一种特殊的混经验战术：不是投入少，而是完全不投入（纯混的玩家事实上已经停止操作了）。这类玩家躲在其他玩家注意不到他已离开的地方，或者甚至使用外挂。

“打金”是指玩家使用其他帐号帮主帐号增加所得。这在多人地下城游戏中非常普通，玩家可以释无忌惮地重复获取资源。这种做法在格斗游戏中也常用，玩家使用他的其他帐号作托，增加主帐号的属性点或提高排名。

简单的解决办法是，检查IP，惩罚滥用游戏的玩家。这个做法的风险是，开发者可能会误惩玩家，例如，如果兄弟两人在家玩同一款游戏。

另一个更好的解决办法是，执行收益递减系统，也就是不断消灭给攻击者少量好处的实体。或者把这个办法再改进一点，即让高级玩家从攻击低级玩家中获益更少。

“越级”与“打金”相反：玩家建立一个低级角色，给这个角色原本只有高级角色才能获得的道具物品等。这个低级角色可以轻而易举地击败与他级别相当的敌人。

“老手新号”是指老玩家使用新帐号假装新手，然后诱杀真正的新手玩家。这在根据角色能力匹配战斗的游戏中非常普遍。例子如最近的《使命召唤》、《星际争霸2》和《英雄联盟》。

解决办法是使匹配系统自我调正：即在几场游戏之后，将“表现特别突出”的“老手新号”玩家匹配相同水平的玩家，这样“老手新号”把手戏就只能使用几次，然后再建立一个新帐号。对于付费游戏，这类不老实的玩家每建一个帐号就要购买一次游戏。在免费游戏中，这只能靠玩家群体的社交规范和开发者的政策了。

“扮鬼”是指不参与游戏的玩家在多人游戏中偷偷把对手的活动汇报给另一名玩家。

“扮鬼”的另一种形式是高水平的玩家通过流服务“现场解说”游戏。同伴可以边观看解说边估计对手的行动。

“帐号共享”是指多名玩家使用同一个帐号达到靠个人需要耗费大量时间才能达到的目标。当帐号共享时，这个目标可能只需要耗费个人少量的时间就能达到了。

“练”是指玩家专注于不是游戏主要目标的目标，比如增加属性点、达成成就等。

“练成就”在多人游戏中表现为，敌方团队的玩家与另一方的玩家合作，这样他就能轻易达成一般情况下需要更高水平和更多投入的成就。

赛车游戏中的漏洞

“短路”是指当玩家发现比正常路线更快完成比赛的路线。这可能简单得像倒退开车，但一般情况下需要玩家发现关卡设计上的错误。

“刷跳”是指玩家重刷和跳进度。通常表现为，玩家死在一个能使他们在前面刷出的地方，或死亡后重刷会极大地增加他的速度。例如，《马里奥赛车》中的彩虹桥，玩家在那里死亡后重刷可以跳过大段路程。

“刷道具”是指玩家可以继续原本限制了使用次数或时间的速度道具。例如，在《马里奥赛车》中。玩家刷道具保持赛车的高速状态。另一个例子是在《F-ZeroX》中，使用分开的得分榜显示刷道具的玩家和没有刷道具的玩家。

游戏物理中的漏洞

“墙跳”是指玩家能够“飞檐走壁”，通常因为游戏世界几何体中的物理不准确或小故障。

在《魔兽争霸》中，在引入飞行坐骑以前，玩家会使用这个漏洞到达原本无法达到的地方。

“带物”是指当玩家跳到某物品上时，他就可以留住这个物品，带着这个物品继续移动。这使得玩家可以跳起来或像坐了喷气背包一样飞行。在之前提到的《辐射3》中，玩家就是靠这种办法直接进入Citadel的。

“超级跳”是指玩家使用一系列二级动作增加移动速度。这些动作一般是跳跃或蹲下。“超级跳”技术因为引擎不同，效果也不同。

保存系统中的漏洞

“复制”是指玩家通过存档留住资源——通常用在玩家通过IAP获得的虚拟货币。玩家收集资源；加载后再收集，这样就能轻轻松松获得大量虚拟货币了。

“克隆”类似于“老手新号”，但不是创建新帐号，而是把保存好的游戏拷贝给其他帐号，然后出售保存好的游戏中的资源换钱，再通过好友“赠送礼物”等社交功能把钱返回给原来的帐号。

解决办法是追踪玩家保存的有效性，或检查“礼物”的来源以判断是否出自合法用户。

“多档保存”是指玩家将游戏保存多次，这样他就可以“完美表现”了。这么做的玩家只要简单地重新载入游戏，直到得到想要的结果。

解决办法是将加载没有正确发生的情况下频繁使用的保存版移除或变为不可用，玩家死亡是典型的情况。不幸的是，这个做法取消玩家在死亡后重新加载的功能。另一种办法是在游戏中使用保存点，而不允许玩家随意保存进度。

“多档保存”类似于“碰运气”—-区别是，玩家可以使用多个存档来保存游戏进度，而只是“碰运气”的玩家必须重新开始游戏（或关卡）。

有些游戏将这种做法当作有效的游戏机制，例如，在《Castle Of The Winds》中，关卡在玩家进入时会随机生成，玩家可以选择重新进入关卡。这是一种原本有损的机制的后备修复办法（更准确地说，有损的程序生成）。

“跳进度存档”是指玩家利用游戏自动保存机制获得好处，比如远程传送到不同的游戏点，或跑到一个自动保存点同时加载存档，这样就把敌人移除了。

如何寻找游戏设计中的漏洞

作为设计师，寻找漏洞是件难事：为了管理游戏世界，你要破坏你精心制作的每一条规则。在非电脑类游戏中，这可能比较容易，因为规则是明确陈述的。而在电子游戏中，规则是含蓄的，玩家必须学习规则，且大多时候要经历不断的尝试与犯错。因为这类游戏的复杂度，一个漏洞可能会被完全忽略，毕竟“合适的游戏方法”在设计师脑中已经根深蒂固了。

要发现设计中的漏洞，你要使用：

1、你的知识、经验和直觉

寻找漏洞模式。有了经验后，你便可以识别出可能导致漏洞的模式，然后提前在设计中将它去除。上文讨论到的所有FPS漏洞都是由关卡设计和AI的互动之间导致的。

从其他游戏中发现漏洞，从而积累寻找漏洞的经验，是非常有意义的。

理解玩家动机。甚至在简单的游戏中，漏洞也可能是无穷无尽的。专注于重要的漏洞。考虑玩家想做什么，关注允许或限制玩家目标的各种系统：

1、玩家想赢

2、玩家想要更多资源

3、玩家想在游戏中百发百中

4、玩家想成为第一名、最快的、最强的、最富的、最靓的、最酷的人

5、玩家想要成就

这些不一定是最容易出现漏洞的系统，但却是玩家最关注的系统，而这些系统中的漏洞最有可能产生重大影响（对玩法、玩家满足感和甚至你的底线）。

不要消自发性游戏性。预测玩家行为可能很困难，并且你的漏洞修补措施可能会限制游戏或抑制积极的突发事件。

2、请其他游戏设计师检查你的设计

其他设计师有可能是找漏洞的高手。设计师通常对系统和规则有一套很好的检查漏洞的办法，并且他们非常了解其他游戏中的各种漏洞。

当然，这个办法不是完美的：

1）不同的设计师可能对什么是漏洞有不同的定义

2）即使有100个设计师检查，也可能忽略某些漏洞

3、测试

测试具有以下优势：玩家没有设计师的偏好；你通常能找到更多玩家来评价你的游戏。

玩家知道他们的游戏世界有规则，他们可以破坏规则达到自己的目的。联赛水平级的玩家通常可以当作平衡性测试者，他们曾在《星际争霸2》和《CS》这类游戏的制作中发挥了非常重要的作用。

数据指标是寻找漏洞的强大工具，特别是当你有很庞大的测试团队时。简单的数值如选择某个角色的玩家人数可能会暴露平衡性问题：如果选择某个角色的玩家比例失调，那就说明有问题了。

《Desktop Dungeons》团队能够发现地下城神坛的漏洞是因为他们查看了玩家数据指标。许多玩家在相同的帐号上创建另一个角色，而这个帐号只解锁了3个神。这让设计师感到困惑，直到他们意识到只解锁3个神的优势。

数据指标在发现普通的漏洞方面也很有用：数据指标显示，《WOW》中的高水平公会在突袭中使用客户端工具，直接跳到最后一个BOSS面前，使游戏事件发生的顺序失调。

热力图—-将游戏地图的数据指标视觉化的图像，是另一种寻找漏洞的好工具。热力图可以显示诸如玩家死亡数、射击发生数、敌人覆盖点和玩家探索路线等东西。热力图直观地显示了地图上的地形问题。BioWare在《光晕3》、《正当防卫2》、《小绿人历险记》《CS：全球攻势》中均使用热力图寻找漏洞，甚至在点击类冒险游戏中也采用这种技术。

（玩家在《正当防卫2》中的玩家死亡数分布图）

4、玩家反馈

一旦游戏发布，就会有大量玩家玩它，接着就会暴露漏洞问题了。在游戏中添加数据指标是非常有用的（因为玩家可能不会像测试者那么积极地反馈漏洞。）不幸的是，你只能靠补丁或升级来解决漏洞。

如何修补漏洞

改变其中一个组件。因为漏洞是因为游戏元素（规则或系统）之间的意外交互作用而产生的，所以漏洞通常可以通过修改某个系统得到修补。例如，上文讨论到的所有FPS漏洞都可以通过改变关卡设计或调整AI得到解决。

改变交互作用。通过改变系统之间的交互作用也可修补漏洞。以FPS为例，在调整AI时把关卡设计考虑进去，使AI根据周围的情况改变行为。

注意：普遍的解决办法VS特殊的解决办法。有些漏洞可以通过引入特殊的规则或例外来解决。例如，在FPS中，可以根据特定的区域设计AI行为：“如果我接近位置（123，456）时，我必须离开板条箱”。也可能使用普遍的规则解决漏洞；例如在FPS中，AI呆能被调整为：“如果我介于两个板条箱之间，我就要离开。”

普遍规则更容易管理。但靠普遍规则修补漏洞可能会引入新的漏洞。特殊规则不影响整个游戏，但可能需要大量特殊规则，这就使排错工作变得很困难。“为什么这个AI靠近大BOSS时就离开板条箱？”

依靠社交规范。在多人游戏中，社交规范可以弥补规则上的破损，特别是当修补漏洞的成本太高时，或者解决方案不明确时。网络司法体系是MMO社交系统的必要部分。这种社交规范可以由行为指南提供，如《魔兽争霸》的针对骚扰的政策，或奖励对社区积极贡献的玩家，这是《Dota2》的计划。

不是bug，是特色

漏洞会破坏游戏，但也不总是。

有些漏洞本身就有很高的技术含量，所以它们不会破坏游戏。在《传送门》的开发者评论中，游戏开发者表示，他们有意留下一些解决益智题的诡计，因为执行这些诡计需要的技术比按正常办法解决益智题更多。

有些漏洞成为新机制。如果它们被使用得够多，可能仍然不妨碍游戏成为一款好游戏，即使已经违背了设计师的意图。在《Quake 3》中，玩家可以使用跳跃加转向的组合来提高速度。这个技术叫作平移跳，是设计师从来没有想过的，但它很快成为游戏的一部分，所以设计师们也决定留下它。

游戏的漏洞甚至可能成为续作的主要机制。在《Starsiege: Tribes》中，移动系统允许玩家使用喷气背包加速下坡。这类似于滑雪，是所有《Starsiege: Tribes》系列的核心机制之一。

有些漏洞对游戏影响极小。这类漏洞可能使游戏的某些部分变得更容易了，但并没有改变游戏的整体难度。在这种情况下，这种漏洞可能成为一种乐趣，如在前文中提到的在《天际》中玩家将桶扣在NPC头上。

有些漏洞“修补”了崩坏的设计。是的，如果你不使用“蛮干”解决某些游戏中的难题，那些难题可能根本解不开。

寻找漏洞是一种娱乐。在制作游戏的比赛，“极速通关赛”使用了序列间断的漏洞，这样玩家就能以尽可能少的时间完成给定的游戏或关卡。

结论

漏洞将永无止境地出现。在其他游戏中积累的漏洞经验和知识可以帮助你避免漏洞，适合的测试可以帮助你找到漏洞。（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）

Loopholes in Game Desig

by Julian Pritchard

I had just finished working on my latest card game; I was rather chuffed with it: the rules were elegant and nuanced: there was a wealth of strategies you could use in the game. I explained the rules to two friends, and they began to play. I was expecting them to be amazed with the game.

Instead, I was amazed with how one had managed to find a neat little trick to — unexpectedly — win the game: a loophole!

After the discovery, the game was never the same. I eventually decided to change the card game into a board game so that the game could keep my original idea, but without the loophole.

After the change in my game, I became obsessed with loopholes in games. I began to research them and find how they could affect games. In this article, I summarize my research. This article covers what loopholes are, and why they are bad, with a big list of generic types of loopholes that can be found in games. The article also gives some advice on how to find and correct these nasty little game breakers.

What a loophole is

If something can be abused, it will be.

— Hyrop’s Law of Loopholes

A loophole can be defined as a flaw in the system that users can exploit to gain an unfair or unintended advantage.

[Fullerton, Game Design Workshop]

Loopholes are often the result of emergence; two or more rules acting together to make something possible that was not thought possible. Loopholes arise when the game rules don’t completely limit or enforce the legal behaviour.

Players find loopholes when they know the rules very well, or by accident. However they find it, the result is always the same: they will use the loophole, regardless of whether it makes the game more fun. A pointed example of players grinding away instead of having fun is with achievement farming.

When given a task, players will find the optimal solutions, even if it ruins their fun. Finding optimal solutions is part of playing the game — it is the designer’s responsibility to create the necessary challenges for an interesting solution; this burden is never the player’s.

Loopholes lead to unwanted player behaviour; the named loopholes discussed below are all words for things the player can do, but the designer does not (usually) want.

Related Concepts

Loopholes are degenerate strategies to play the game. Among all available strategies, a dominant strategy has the best chance of leading to success. A degenerate strategy is a dominant strategy that always leads to success. (Not all dominant strategies are degenerate: the prisoner’s dilemma is a classical example.)

Loopholes are often bugs, but only bugs that can be exploited by the player are loopholes.

Many loopholes are sequence breakers (that is, they allow the player to experience events in a different order than was intended), but only sequence breaks that benefit the player are loopholes.

Many loopholes are exploits — ways to play the game that goes against the spirit of the game. But not all exploits are loopholes. For example, some exploits require special tools for hacking the game. These are generally considered cheating.

Examples of loopholes

In Bastion, players can deliberately fall off a barge, forcing the game to respawn them in a non-combative state on a moving barge. In this way, players can traverse part of the level without having to engage in combat. A secondary effect of this loophole is that the narrator does not realise what’s happening; he happily talks about combat as if it is still happening.

In an earlier version of Desktop Dungeons, there was three altars in each dungeon. Each of these altars randomly selected one god from a possible nine gods. These gods were unlocked one-by-one through quests. Players realised that if they have only unlocked three gods, they could know which three gods would spawn with certainty. Thus, the randomness of gods was removed. The developers have since fixed this loophole by making only one altar available in a dungeon until the player has unlocked four gods.

In Rock of Ages it is possible for a rock to hit the door, and then bounce off the pathway. The game then places the rock back on the pathway, allowing the player to hit the door twice with only running the course once. This is a detrimental loophole because the game requires the player to traverse a course before they can hit the door.

In Magic The Gathering the Chaos Orb card removes any card it landed on from play. Some players would tear it up and sprinkle it on their opponents cards to remove multiple cards from play. When a player tried this the first time, the judges ruled it legal, since there was no rule against tearing the card up.

Fallout 3 has a loophole where the player may skip a large portion of the game by going straight to one city (The Citadel), and then using any item to jump into the city, instead of completing the quests to get inside.

In The Elder Scrolls V: Skyrim a player can place a bucket on NPC’s head and rob him blind without the NPC realising it.

In Deus Ex players could uses LAMs, a grenade which could be placed as a proximity mine, as a ladder. This allowed players into areas in ways that were not intended.

A ten year old hacker exposed the following generic loophole at DefCon: in social games that run on mobile devices, you can set the time forward and receive reward without having to wait for it.

More examples:

Loopholes in Sid Meyer’s Civilisation IV

Loopholes in Skyrim (levelling up)

Loopholes in The Sims 3

Playing games in different ways

Image from xkcd.com/115

Why loopholes are bad

According to Adams, gameplay is

The challenges a player must face to arrive at the object of the game.

The actions the player is permitted to take to address those challenges.

Loopholes interfere with both these aspects of gameplay.

They remove the challenge of the game. As mentioned earlier, players will take the easiest path towards their goal. A loophole introduces a new, easier path, effectively removing the path of challenge the designer intended. Without challenge, the gameplay is ruined.

They remove meaningful choice. Loopholes mess with the balance of the game, and an unbalanced choice is almost always a no-brainer. The existence of a loophole limits the range of interesting actions the player can take..

There are two additional reasons why loopholes are bad.

They remove fairness in multiplayer games. A game that is not fair is not fun, because all players would have to use the loophole to stay competitive. Designers should always strive to make games fair.

They can break the fourth wall. When a player uses a loophole, the game reacts in a way that exposes its limitations and underlying machinery. This can remove the sense of atmosphere and story from the game, because things no longer make sense without looking outside the magic circle. The narrator glitch in Bastion mentioned above is the perfect example.

General types of loophole

The following behaviours can occur in any type of game. Many games rely on these behaviours for their gameplay, but when they were not the behaviours intended by the game designer, they show a loophole.

Memorizing is when the game or game AI follows patterns that players can memorize.

Pac-Man is famous for this — instead of responding to enemy behaviour, the best players memorize sequences of moves they have to make to complete a level.

The easiest way to avoid players from memorizing game events is to introduce a random element in the game, either in AI behaviour, or item and AI placement, or even just in the timing of the AI.

Predicting is when the player can learn the logic of the AI, and easily defeat it by predicting its next action.

Prediction can be avoided by introducing random elements as explained above, or making AI more nuanced (essentially, making it depend on more input variables).

Brute forcing (also called permutation play) is a way of solving certain kinds of puzzles, usually where the player must figure out the correct combination of moves, digits, levers, buttons, or something similar (there are many of these kinds of puzzles in Machinarium, for example).

In some cases, brute force is the intended method of solution. But when the designer intends the player to use logic and clues provided to solve the puzzle, solving it by brute force is a loophole.

There are two ways to fix this:

Add more combinations (for example, adding a lever to a puzzle doubles the number of possible solutions), so that brute force techniques become infeasible.

Make the logic or clues more transparent.

Pixel hunting is a special form of brute forcing that is common in point-and-click adventure games. Pixel hunting is where the player mouses over (or clicks, depending on the controls) the entire screen until a indicator pops up to show that they had found an interactive point.

Pixel hunting can occur in any game that highlights interactive points only when the mouse hovers over them or they are clicked, such as a FPS reticle turning red when passing over a hidden enemy.

In some cases making the player hunt for pixels is intentional, such as resource scanning in Mass Effect 2.

Hustling is when a player exploits the dynamic difficulty adjustment of a game by playing lower than her potential. This makes the game easier, and eventually allows the player an easy victory. This is similar to pool hustling in the “real world”.

Hustling is most common in the single-player mode of racing games. Racing games use dynamic difficulty adjustment, called rubber band AI, which adjusts the AI vehicles’ performance to match the player’s: the faster the player, the faster the AI. A player hustles by keeping in second place until the last lap (even if she can pass the first vehicle). With the player in second place, the game will not increase the difficulty; it thinks that the player is being challenged.

To fix rubberband exploits can be difficult. The racing game Pure uses a sophisticated alternative to the rubber band method. The system dynamically sets the AI some distance ahead of the player from the start. This means that the player is continually playing catch-up throughout the race until the end, where she can narrowly beat the AI. Like with rubber band AI, the player is generally capable of victory, but she can’t hustle.

Fortune hunting occurs in games with random level generation. The player briefly glances around the level to decide if they feel the level is easy enough for them to complete; if not, they simply restart the level in the hope of a more favourable one. Like the hustler, the fortune hunter is playing the game at a difficulty lower than the one that designer intended.

The designer can prevent fortune hunting in several ways:

By normalizing level difficulty so that each randomly generated level is about the same level of difficulty (this can be hard, and requires a good understanding of statistics and the game mechanics).

By not allowing a new level to be generated until the previous one has been played.This requires that you can guarantee that all your levels are fair. Otherwise, a level may be generated that frustrates the player to the point of quitting the game permanently.

To make it more difficult to judge the level difficulty until the player has invested enough time not to want to quit the level.
Loopholes in FPSes

Edging is where the player stands around a corner and shoots a part of the enemy while the enemy can’t see the player. This loophole can be countered by having the enemy AI seek out the source of the damage.

Picking is the same as edging, except that the player hops out from the corner, shoots, and returns to hiding. As with edging, this loophole can be corrected by making the AI move towards the players to attack.

Wedging can be used on enemies with a short attack range: the player lodges an enemy in a place where it cannot attack her from. This allows the player to pick off this enemy with ease.

Ways to counter this loophole are to give the enemy a long range attack, to allow it a means to reach the player by fixing the level design or improve the AI, or to create entities which force the player towards it (using a rope, for example).

Kiting is when the player can move faster or shoot further than the AI. This allows the player to move backwards and attack the AI while not receiving damage.

Camping is when a player stations herself where enemies can’t see her, and attacks enemies from such a place. Camping is normally done from a distance and with a sniper weapon.

Simply making enemies return fire may cause the player to feel cheated. A proper solution is to make the enemies move towards the player. Another strategy (especially useful in multiplayer games) is to carefully design levels without any good camping spots, and give enough feedback so that players can learn the positions of campers, for example, the Heartbeat Sensors, Unmanned Arial Vehicles (UAVs), and KillCam in Modern Warfare 2.

Splashing is similar to camping. The player positions herself far away from the enemy and shoots an object that does splash damage, such as a grenade, at the enemy.

The are two solutions to this problem: first, the AI can be made to avoid splash damage of oncoming missiles with a bit of physics math; second, the AI can be made to seek out the player who launched the attack.

Serializing is when a player kills an entire group of enemies by picking them off one-by-one. This is typically happens in narrow spaces, or if the AI causes enemies to separate from the group. This is a loophole if the intention was to make it more difficult to take out groups, and give the player an opportunity to choose which enemies to take out first.

The simplest fix is for the enemy to trigger an alert state in the nearby enemies which allow them to move off in a group towards the player. The combat space also needs to be designed carefully to prevent serialisation.

Loopholes in multiplayer games

Turtling happens in games with resources — typically strategy games — and there are more than two players. When two players engage in combat, both will consume resources. This puts the combatants at a disadvantage since they both lost resources in the engagement. In the meantime, the turtle is better off than both, since she did not need to spend any resources, giving her an advantage in the next combat against either player.

This effect can lead everyone in the game to play turtle, which of course prevents the game from moving forward. The solution is to encourage aggressive play by awarding the winner of each battle with enough resources to offset the losses suffered in that battle.

Killing the leader occurs in games where a scoreboard is available during play. Players attack the leader, since she is the person most likely to win, often forming coalitions to achieve this goal.

With the multitude of players attacking the leader, it is likely that they may suffer damages to a point where they can’t recover from them, and they no longer have any chance at victory.

A simple solution is to remove scoreboards from the game. A more complex solutions is to prevent players from cooperating with one and other.

Sandbagging is is a form of hustling caused by the killing-the-leader effect. Good players are aware that others are likely to attack them if they are seen to be doing well. To prevent this, they deliberately underperform until they can act to their full potential and win the game. Note that the killing the leader effect serves as built-in dynamic difficulty adjustment.

The solution to this is the same as that for killing the leader: remove the leaderboard. If players don’t know who the leader is, there is no reason to play sub-optimally.

Kingmaking is when the player lower down in the scores is not able to win, but by her actions she can decide whom among the leaders does win. These actions can be in the form of sending resources to another player, or combining the armies in a coalition. This introduces an element of diplomacy into the game, where a player can win based on relationships and not skill. (As always, it is just a loophole if this is unintentional).

The solution to this is the same as the one for sandbagging and killing the leader: remove scorebords.

Experience leeching takes a variety of forms, but the general formula is the same. A player gains benefit of participation without putting in the required effort involved to achieve the outcome.

In games where experience is awarded to the player who lands the killing blow, leechers are passive in combat until the last moment, when they jump in and kill the enemy to get the experience, at little risk of dying.

In games where experience is awarded to all players in range of the kill, leechers can stay passive all the time; as long as they trail behind, they can get experience without having to take any risks.

Power leveling is a special kind of leeching. A player groups with a high level player who also kills enemies of a high level. Because of the level difference, the low level player will gain a wealth of experience causing them to level fast.

Simple solutions are to assign experience to the player who does the most damage, or to assign experience in proportion to the damage dealt.

AFK loopholes are a special form of experience leeching: instead of putting minimal effort, though, the player doesn’t put in any effort (they are, in fact, away from keyboard). The player hides in a place where other players will not notice that they are AFK, or even employs some form of bot.

Boosting or alt farming or alternate-account farming is a method where a player uses an alternate account to enhance the gains of her primary account. This is widespread in MUDs, where the players have a resource that they can attack repeatedly without fear of retribution. Boosting is also common in fighting games, where a player will “fight” against the character of her second account to boost her stats or position in the leaderboards.

A simple solution is to check the IP usage and discipline the user for abusing the game. The problem with this scheme is that the developer may punish a player unfairly, for example, if a player beats her brother at a game that they play together.

A more elegant solution is to implement a system of diminishing returns, where the continued killing of a single entity gives less gains for the attacker until it no longer to make sense to attack. This can further be improved by also making higher level players receive less benefits from attacking lower level players.

Twinking is the opposite of alt farming. It is when a player creates a low-level character and gives it the benefits that are intended for a high level character. The twink is kept at a low-level so that it may defeat opponents of similar level with great ease.

Smurfing is hustling by using a new account and pretending to be an inexperienced player to lure in and kill players that are actually inexperienced easily. This is common in games where there is matchmaking based on metrics tracking player capabilities. Examples include the recent Call of Duty games, the leagues in StarCraft II, and League of Legends.

Matchmaking systems are self-correcting: metrics will move the smurfer to matches with equally skilled players after a few games, so she can only use this technique a few times before having to create another new account. And with pay-to-play games, the smurfer is required to buy the game each time she wants to create a smurf account. In a free-to-play game it is up to the community and dev team to find a solution using social norms and policy (discussed more in a section below).

Ghosting is when a non-playing observer in a multiplayer game communicates to one player, or team, the actions of their opponent.

A sub form of ghosting is called stream sniping this is when highly skilled player broadcast their games live on a streaming service. Their opponents may then watch the stream and counter their opponents actions as they are watching them.

Account Sharing is when multiple people use the same account to achieve a goal that would need a large time commitment by a single player. With account sharing, such a goal can be reached with only a modest time commitment by each player.

Farming is when players focus on a goal that is not the main goal of the game. This can be something such as increasing their stats, or gaining achievements. Each of which would normally prefix farming when in action.

Achievement farming, in a multiplayer games, is when players of opposing teams cooperate with one and other so that players can easily gain achievements that would normally require skill and investment in the game.

Loopholes in racing games

Short circuiting is when the player finds a faster route to complete the race than the intended one. This can be as simple as driving the course backwards, but normally requires the player to find an error in the level design.

Spawn jumping occurs when the player respawns and has gained time. This normally involves the player dying in such a place that it is possible for them to spawn ahead, or dying in such a way that would dramatically increase her speed. An example of this is the rainbow bridge in Mario Kart, where a player could skip half the race by spawn jumping.

Perma boosting is when the player is able to continually use a speed boost that is only supposed to be used seldomly, or in a limited amount. An example of such an exploit is snaking in the Mario Kart games, where players use power slides to always have a boost on the vehicle. Another example is in F-ZeroX, where separate scoreboards are used for players who perma boost and those who don’t.

Loopholes in game physics

Wall jumping is when the player is able to climb up a wall by jumping against it, usually because of inaccurate physics or small glitches in the world geometry.

In World of Warcraft, before the introduction of flying mounts, it was possible to use this loophole to reach places in the game that the player shouldn’t have been able to.

Bootstrapping is when the player jumps onto an object that she ‘holds’. She just moves up and also brings the object up with her. This allows the player to jump up or fly as if she had a jetpack. The Fallout 3 loophole mentioned earlier relies on bootstrapping for the player to get access to the Citadel.

Bunny hopping is when the player uses a series of secondary movements to increase the movement speed. These movements typically involve jumping or crouching. Bunny hopping techniques vary from engine to engine.

Loopholes in saving systems

Duping is when there is a resource that persists through saves — generally a currency the player gains through an in-app purchase. The player gathers the resource; loads and gathers it again, while they are in turn getting richer for not doing any work.

Cloning is similar to twinking, but instead of creating a new account the player copies a saved game into a dummy account, sells the resources of the saved game for currency, and sends the currency back to the original account via a form of social integration where friends can ‘gift’ things to one and other.

The solution is to track the validity of player saves, or to check where the ‘gifts’ are coming from to be sure that they are from a legitimate user.

Save scumming is when a player makes multiple saves so that they can play a ‘perfect’ game. The player creates a number of saves and simply reloads one until they get the result they want.

A solution is to remove, or disable, a save that is frequently used without the correct condition for the load to happen — player death is typical. This, unfortunately, removes the player’s ability to reload when death is certain even before it occurred. An alternative is to make the games use save points instead of free saves.

Save scumming is similar to fortune hunting — the difference is that a player can progress with save scumming, while a player that merely fortune hunts has to restart the game (or level).

Some games make statistics manipulation a valid game mechanic, for example, in Castle Of The Winds levels are randomly generated on player entering, and players can choose to re-enter the level. This is a kind of fall-back-fix for otherwise broken mechanics (more precisely, broken procedural generation).

Save jumping is when the player uses the game auto-save system to their advantage. The player can do things such as teleporting to a different game point, or run to an autosave point while fighting to load the save and remove the enemies.

How to find game design loopholes

As a designer, finding loopholes is a challenge: you are trying to break the very rules you crafted so carefully to govern the game world. In non-computer games this may be easier because the rules are stated explicitly. In video games, the rules are implicit, and requires a player to learn the rules, mostly, through trial-and-error. Because of the complexity of some games, a loophole may be completely overlooked simply because the “proper way of playing” is ingrained in the designer’s head.

There are four ways to find loopholes in your design.

1. Use your own knowledge, experience and instincts

Look for loophole patterns. With experience, you will start to recognize the patterns that can lead to loopholes, and remove them from the design early. All the FPS loopholes discussed above arises from the interaction between the level design and AI.

Drawing from a large knowledge-base of loopholes in other games in your genre can be very helpful, and it’s a good idea to build such a base for yourself.

Understand player motives. Even in simple games, the possibilities for loopholes are endless. Focus your attention where it matters. Consider what players want to do, and pay attention to the various systems that allows or limits these goals:

Players want to win.

Players want more resources.

Players want to get to every spot in the game.

Players want to be the first, the fastest, the strongest,the richest, the prettiest, the coolest.

Players want achievements.

This will not necessarily be the systems with the most loopholes, but it will be systems that players will pay most attention to, and loopholes in these systems are most likely to have important effects (on gameplay, player satisfaction, and even your bottom line).

Don’t Kill Emergence. Trying to predict player behaviour can be tricky, and there is always the risk that your loophole corrections unnecessarily limits the game, and removes the possibilities of positive emergence.

2. Ask fellow game designers to check your design

Fellow designers can be great at finding loopholes. Designers have a good way of looking at a system and its rules and finding where to break them, and they typically have a vast knowledge of various loopholes in other games.

Of course, this method is not perfect:

different designers may not agree on what are the loopholes of the game; and

even a hundred game designers may still overlook some loopholes.

3. Test

Testing overcomes some of these problems: gamers don’t have designer’s bias, and you can generally find more game players than game designers willing to comment on your game.

Gamers know their game worlds have rules, and that they can break these rules to their advantage. Tournament level players are often used as balance testers and have been extremely important in the making of games such as Starcraft 2 and Counter Strike: Global Offensive.

Metrics are a powerful tool for finding loopholes, especially if you have a large test group. A simple statistic such as number of players that choose a certain character may point to a balance issue: if a disproportionate number of players choose a certain character or combination, you know there is a problem. The course blog Game Balance Concepts gives an extensive overview of the use of metrics in game design.

The Desktop Dungeons team was able to pick up the loophole with the gods by looking at the metrics of their players. A number of players were creating alternative characters on the same account where they unlocked only three gods. This puzzled the developers, until they realised the advantage of only unlocking three gods.

Metrics are also useful to pick up more general exploits: metrics exposed a highly skilled guild of WoW players that used a client side tool to delete a wall during a raid and skip to the last boss, making game events happen out of the planned order.

A heatmap — a visual depiction of a metric on the game map — is another useful tool in finding loopholes. A heat map can show things such as player deaths, shots fired, enemy cover and player exploration. Heatmaps make it visually apparent where there are topographical problems with the map. See for example how this technique was applied in Halo 3, Just Cause 2, Replica Island, Counter Strike: Global Offensive, by BioWare, and even in point-and-click adventure games.

Player deaths in Just Cause 2.

4. Use feedback from players in the field

Once a game has shipped, and your game is played by a large number of players, even more loopholes will be exposed. Adding metrics to your games can be very helpful to expose loopholes in these circumstances (players may not want to report loopholes as eagerly as testers). Unfortunately, you will only be able to fix with a patch or update.

How to fix loopholes

Change one of the components. Since loopholes arise from the unintended interaction of game elements (rules or systems), a loophole can generally be fixed by making a change to just one of these systems. For example, all the FPS loopholes discussed can be fixed by either changing the level design, or by changing the AI.

Change the interaction. Loopholes can also be fixed at the points where systems that cause them interact. Taking the FPS examples, the AI can be adjusted to take the level design into account, so that alternate behaviours are used based on the topology of the surroundings.

Beware: general versus specific solutions. Some loopholes can be fixed by introducing very specific rules or exceptions. For example, in an FPS game, AI can be developed for specific zones: “if I am close to position (123, 456), I need to move away from the crates”. Alternatively, problems can be fixed with general rules; in an FPS, for example, the AI may be adjusted “if I am between two crates, move away”.

General rules are more elegant and easier to manage. But adding general rules to fix loopholes may introduce new loopholes. Specific rules don’t impact on the overall game, but many may be needed, leading to debugging nightmare. “Why is this AI moving away from crates when he is near the big boss?”

Rely on social norms. In multiplayer games, social norms can make up for broken rules. This is especially useful when a loophole would be too expensive to fix, or a solution is not clear. Online justice systems are an essential part of MMO social systems. Such social norms can be provided by behavioural guidelines — such as the World of Warcraft harassment policy — or rewarding players who positively contribute to the community, such is the plan for Dota 2.

It’s not a bug, it’s a feature

A loophole can destroy a game, but not always.

Some loopholes require considerable skill in themselves, and thus they don’t break the game. In the developer commentary for Portal. The developers said they left trick methods of completing the puzzles in because they required more skill than completing the puzzle normally would.

Some loopholes become new mechanics. If they are rich enough, it can still be a good game, even if it is not the one the designer intended. In Quake 3 players could use a combination of directional jumping and turning to increase her speed. This technique, called strafe jumping, was never planned for, but it soon became an essential part of the game, and the developers decided to leave it in.

The loopholes in a game can even become the main mechanics of the sequel. In Starsiege: Tribes the movement system allowed players to attain very high speeds by using their jetpack to go down a hill. This is referred to as skiing, and is one of the core feature of every tribes game.

Some loopholes have little effect in the greater scheme. They may make one small part of the game easier, but overall don’t change the difficulty. In this case, they may become a source of amusement, such as the bucket-on-the-head Skyrim loophole mentioned earlier.

Some loopholes “fix” broken design. Yes, if you take out the ability to bruteforce puzzles in certain games, they may be totally unsolvable.

Finding loopholes is a sport. The meta game of speed runs use sequence breaking loopholes so that the player can complete a given game or level thereof in the least amount of game time possible.

Conclusion

Loopholes pop up from time to time. Experience and knowledge of loopholes in other games will help you avoid them, and proper testing to find and remove them when they do slip through.(source:devmag)