欢迎来到本课程的第四节课：关于游戏设计的基本介绍。务必确保在继续阅读前先了解教学大纲和课程信息。今天我们将讨论游戏中的系统动态。本文将严格遵循我们的教科书（《Game Design Workshop》第5章，《Challenges for Game Designers》第2章以及《Salen and Zimmerman Rules of Play》的第13，14，16，17和18章）。我们之前曾讨论过规则的使用。作为游戏设计师，我们会使用规则去决定玩家所采取的行动以及这些行动的结果。在数字游戏中，游戏逻辑经常能够提供游戏的部分规则。你的游戏的视听表现（甚至是游戏的故事）并不是游戏形式元素的组件。当视听元素影响着你的游戏的形式结构时，它将被当成游戏规则的元素。Salen和Zimmerman便区分了基本规则和操作规则以及隐含规则。
在2011年GDC大会上的演讲中，Clint Hocking提出了一个问题，即游戏如何为玩家创造意义，并通过动态去解释游戏创造的意义而回答了这一问题。他将这一理念与Hunicke，LeBlanc和Zubek名为《MDA: A Formal Approach to Game Design and Game Research》的研讨论文联系在一起。该论文是最先尝试形式化游戏设计的内容之一，并得到了许多游戏设计师的采纳。它认为游戏系统包含了：
关于意外的一个典型例子便是Conway的生命游戏（游戏邦注：英国数学家John Horton Conway在1970年发霉的细胞自动机），它遵循了细胞网格中的一个非常简单的规则集：
Introduction to Game System Dynamics
Welcome to the fourth week of class in the course: Basic Introduction to Game Design. Make sure to read the syllabus and course information before you continue. Today, we are going to discuss system dynamics in games. This text follows closely from our textbooks (Game Design Workshop, Chapter 5, Challenges for Game Designers, Chapter 2, and Salen and Zimmerman Rules of Play chapters 13,14,16,17,18). In previous lectures, we have discussed the utility of rules. As game designers, we use rules to determine the actions players can take and the outcome of those actions. In digital games, the game logic often provides parts of the rules of your game. The audiovisual manifestation of your game (even the story of your game) is however not considered a component of the formal elements of games. When audiovisual elements influence the formal structure of your game, this should be considered as a factor of your game rules. Salen and Zimmerman distinguish between constituative rules and operational rules as well as implicit rules.
Constituative rules are all about a game’s internal events. They are the main logic behind your game. In a digital game, these are contained directly in the code of your game.
Operational rules are all the rules needed to run the game (not just the constituative or internal events) including all external events related to your game, such as input and output of the game, the way that you express choice in your game and how outcomes are defined for players.
Implicit rules are the unstated assumptions of a game (often similar to a player’s honour code, but also relating to the nature of the computing platform that your game runs on). Implicit rules often relate to the contextual situation of a game that we are taking for granted. However, this contextual situation can be played with, to experiment with innovations in game design.
Games as Systems
As we have discussed in class before, a good way to understand games is to break them down into systems. Systems themselves are defined as a set of elements that interact with one another to form an integrated whole. A system has a boundary and surrounding elements. We already see that this definition comes close to our understanding of games as a magic circle with a boundary that delineates it from the outside world. To create better systems, we need to understand basic system principles, such as interaction quality, system growth and the change of the system over time. When a system is set in motion, the elements of the system will interact to produce a common goal. The elements of a system guide its interaction quality. Similarly, in games, the formal (and dramatic) elements that we have discussed before will create a complex and dynamic player experience when set in motion. Before looking at how systems react when set in motion, it is important to understand their basic elements. Several factors of these elements determine how the system will behave when set in motion.
However, there is even more to systems as they are distinguished by their features that all influence the state of a system:
Objects or elements, which are defined by all of the below items
Structure or properties
Objects are the basic building blocks of a system. Systems have pieces that relate to one another and these pieces are the objects or elements of the system. They can be:
Physical. For example: game pieces, the squares on a grid board, the lines on a sports field, the players themselves.
Abstract. For example: In-game concepts.
Both. For example: Player representations that can be both abstract and physical.
In Settlers of Catan, you have many different game objects. The objects in Settlers of Catan are the player and robber pawns, roads and settlements/village pieces, cards for development or resources, special points (largest army, longest road), terrain tiles with resources, terrain numbers and dice. All these objects in the board game make up the game system. They all have properties, behaviours and relationships. If any of the objects were missing, the game would not proceed as designed. For example, if there were no settlement pieces or roads, the players could not indicate that they have built something. If the resource tiles were missing, play would be meaningless, because it would not be clear how new resources would be gathered or which player would earn a specific resource. Without a dice, the chance element of the game would be missing and the game would change completely (although the dice element could be replaced with a skill-based player challenge).
The below example shows us how some Settlers of Catan objects (e.g., a road, a knight, a settlement and the city expansion) has some costs attached to it. This is a very easy-to-understand example of how game property values work. For example, a road costs 1 wood and 1 brick. Not only are these the cost values of the road object, but they already establish the relationship (another system feature) between roads and resources, such as wood and brick.
Object forms are defined by attributes that are either physical or conceptual in nature (see above). Properties are the sets of values that define the nature of game objects. For example, in role-playing games, characters (and items) can have values, such as strength, vitality or experience level. The audiovisual media representation of a game object is also considered a property value (e.g., the sprites or the artwork associated with the game object). The properties of a game element form a data block that is able to describe the interactions that are possible with a game object in the game system. The more complex an object is in a game system, the less predictable the interactions with this game object become.
In the above example, we can see how a game object – in this case a weapon in Borderlands – is defined by its attributes or properties. Imagine if you had to put this “gun” object into a database, you would need to specify all these properties. For example: a name, what type of weapon it is, what make, damage, accuracy, fire rate, enhancements, clip size, money value, an image or visual model representing it. You can see how important it is to think about all the details of your game objects when you are designing a game. You will later spend a lot of time tweaking and balancing these values. Many game designers prefer to have these values saved in a spreadsheet (or – sometimes – database software) to be able to calculate the changes of values on in-game interactions. Especially, in-game combat relies heavily on how properties create different relationships in your game systems (e.g., properties determine how effective units are in combat). Damage calculations often involve rules relating to game object properties as well as chance.
We can see behaviours most commonly in artificial intelligence (AI) scripts executed for non-player characters (NPCs) in games. However, behaviours can also be seen on cards in the above example of Settlers of Catan (e.g., the settlement card instructs players: “When you build this settlement, you may flip over the destiny card.”). Behaviours refer to the potential actions that game objects could perform during a given game state.
The more actions are possible for a game object, the less predictable the behaviour of the game object. The constituative rules of our games inform what behaviours are possible in a game, but the operational rules can still influence behaviours, often leading to emergent gameplay dynamics. One thing to keep in mind regarding behaviour complexity is that more gameplay complexity does not always equal more fun of playing.
Having relationships among one another is one of the defining characteristics of elements in a system. If we have a random set of objects with properties and behaviours that do not relate to one another, we have a collection, but not a system. In games, relationships are easy to express. For example, by defining the location of objects on a game board or numbering the cards in a card game. Relationships can consist of fixed, linear relations, loose object relationships, or relationships, which can change during gameplay. The number hierarchy of a card set determines a logical relationship between the cards in a deck. The definition of the relationships of system elements is largely responsible for the dynamic experience that occurs when a system is set in motion. Some objects might only have loose relationships with other objects in a system that are triggered when an object is close to them or when a game element is set to a specific state. One of the most interesting aspects of relationships is that they can change based on player choice (as determined by the operational rules of the game) or through chance-based events.
Mechanics, Dynamics, Aesthetics
In a GDC 2011 talk, Clint Hocking asked the question of how games create meaning for players and answered the question by explaining that games create meaning through their dynamics. He relates this idea back to a workshop paper from Hunicke, LeBlanc and Zubek titled MDA: A Formal Approach to Game Design and Game Research (PDF). The paper was one of the first attempts to formalize game design and has since been adopted by many game designers. It defines a game system as consisting of:
Mechanics. This refers to specific game components at the core level (i.e., the level of data representation or algorithms or rules).
Dynamics. This is the putting in motion of the mechanics, the run-time behaviour of the mechanics when the player interacts with the game. It is also value-changing loop of inputs and outputs of player and game system over time.
Aesthetics. This refers to the experience of the player, their desired emotional response when they perceive the look and feel of the game system and interact with it.
Clint Hocking re-appropriates MDA as RBF to make his (and many other game designers’) interpreted meaning of this theoretical structure a bit clearer:
Rules. Mechanics are equivalent to the rules of a game.
Behaviours. Dynamics are run-time behaviours of the game-player system.
Feelings. Aesthetics are the feelings that the game evokes in the player.
The talk then discusses an example of MDA put into action as discussed by Stephen Lavelle in the game Spelunky.
We can examine MDA put into action by looking at the whip weapon in Spelunky. The mechanic of the weapon is that it has an animation attached to it that raises the whip before its use, it also means that the hit box of the whip goes behind and above the player character. This is the whip mechanic.
The dynamic of the whip is that it is a slower weapon that makes it harder to attack flying enemies. However, if deliberately used, the whip can be deadly as it hits enemies above you.
The resulting atmosphere and experience of deliberation is that Spelunky feels a bit smarter than shoot ‘em up games. This refers to the feelings that the player has when playing the game. The question that Hocking asks in his talk is whether the meaning (and the feeling of of premeditative deliberation in Spelunky) comes from the rules governing the whip or from how the player uses the whip. The trouble of understanding how dynamics work comes from trying to understand what exactly play means as a verb. Play can be used outside of a gaming context as a verb, too, for example when playing music. Is play just the act of performing on data (e.g., the notes on a sheet of music or the rules in a game) or does it give deeper meaning exactly by how you perform this as an individual? The feeling and appreciation of the data that a player performs on is what ends up creating the experience for themselves (and potentially others). Hocking thinks that game designers can emphasize either author-driven games, where most of the meaning comes from the mechanics and not much interpretation is allowed for the player (Spec Ops: The Line comes to mind again) or player-driven games where designers abdicate authorship as much as possible to their players. In the video below, you can see an interesting example of how an extremely rare reward (remember that value is tied to scarcity) in a game like World of Warcraft can influence player experience (make sure to listen to the sound in the video).
Complexity of Systems
“Complexity is not just a matter of a system having lots of parts, which are related to one another in nonsimple ways.” (Jeremy Campbell)
Game systems are possibility spaces (e.g., the possibility space of Tic Tac Toe can be modeled as a tree structure). The options that you chose determine the dynamics of the system when it falls into place. Complexity of a system becomes an important factor in the dynamics of a system. Christopher Langton (as mentioned in Chapter 14 of our Rules of Play textbook) understands the complexity of systems at four levels:
Fixed systems do not change. The relationships of the elements in the system remain the same (like a black TV screen).
Periodic systems repeat the same patterns over and over again. If you had a messaging system, where a single messenger just runs back and forth between two factions, you have a periodic system.
Chaotic systems have elements that are constantly changing, but are random in their object states and relationships.
Complex systems, finally, are not random and dynamic in their element relationships, but they are more complex and less predictable than periodic systems.
“Emergence is above all a product of coupled, context-dependent interactions.” (John Holland)
Complex systems are quite rare and often depend on a lot of conditions working in tandem to create the complexity. Simple rule sets can often lead to complex gameplay experiences. When systems generate complex and unpredictable behaviour patterns based on simple rules, we call this emergence.
A good example of emergence is Conway’s game of life, which follows a very simple rule set on a cell grid:
1.Cell birth. A cell becomes alive in the next generation (next round or phase or step in the algorithm) if three of the neighbouring cells are alive.
2.Cell death by loneliness. A cell is dead in the next generation if it has less than two alive surrounding cells.
3.Cell death by overpopulation. A cell is dead in the next generation if it is currently surrounded by more than four alive cells.
The glider is a walking variant of the game of life rules.
Emergent systems provide an interesting complexity for game designers as simple rules can often lead to beautiful and complex gameplay scenarios. On the other hand, these systems can be very hard to balance.
Economic System Examples
We create value in games by making game objects either scarce or making them really useful for players (principles of scarcity andutility). Some games also allow us to exchange resources among ourselves (between players) and with the game system. Allowing simple trades in games forms the basic economy of most games. Often the trades are limited and the economy in a game is controlled and does not resemble any real-life economy. To create a basic economy, you should allow the exchange through:
Items. These are the objects being traded. Often they are game resources and other collectible things in games for which you can barter.
Resources. These are the entities conducting the trades. Often they are players or some form of a bank or a game auction house.
Methods. These are the opportunities for trading. These can be in-game markets, for example.
To facilitate trading, economies can use currencies. The prices of objects depend on the market controls that game designers put into place (e.g., things can be free, fixed price or controlled by the market). Similarly, trade opportunities in games can be regulated or allow complete freedom of trade.
Bartering systems in games can be simple or complex. A simple example of bartering is the game Pit, where the goal is to corner the market. The number of cards in the game is fixed. This provides a stable amount of product for the economic system. The values on the cards also do not change. All trades happening in the game must be for equal numbers of cards, which essentially means that the value objects in the economic system have a fixed price. These market regulations in the game mean that economic growth in the game is not possible. A more complex bartering system example is Settlers of Catan (again). Here, the values of resources fluctuate depending on how much of a resource is produced (which is tied to the randomness of the dice and the assignment of numbers to resource tiles at the beginning of the game). This also changes the total amount of resources (i.e., the product) available in the economy. While the 4:1 trading system (with the game bank) serves as inflation control, the high likelihood of a seven (according to a normal distribution) being rolled with the dice punishes players holding too many resource cards on hand. Any player with more than seven cards will have to return half their hand to the bank.
Market systems employ currencies for their trades. This makes them more complex than bartering systems. A simple market example is the board game Monopoly, where the number of real estate available in the game is finite, but the prices for the real estate fluctuate significantly based on player goals. Players start with a fixed amount of money, but have a steady income by passing Go (the starting square) every round. There is also no cap on available money from the bank. The interesting aspect of the market is how the value of real estate properties are determined. First, a player may purchase the property at the title deed, but if they decline to purchase at that point, the property goes up for an auction among the remaining players. The market value here is determined by player goals and by the competition arising from already purchased properties (since there are significant benefits to having properties of the same colour).
More complex market examples can be found in MMORPG auction houses and virtual economies. Players start out with little resources and will have to put time into gathering virtual resources (a process that also relates to gathering experience and is called grinding) within those economies. Trading is possible between players and with the game system (in shops). Supply and demand influence the market values in this economy. See also the above video about virtual inflation.
Feedback loops are important parts of the game system. They can help you to balance your game system or make it more competitive. For example, if you have a game system, where whenever a player scores a point, they get a reward like an extra turn, then you are reinforcing the positive effects of your reward and create an advantage for that player. This promotes divergence in the game. Good people will become better much faster. This is called a positive feedback loop and it can be used to accelerate gameplay, because players are able to move faster toward their goal and it makes it harder for other players not doing so well to catch up. Depending on whether your game depends on a scoring evaluation, this loop can lead to the endgame quickly. Player-system relationships are reinforced by a positive feedback loop.
On the other hand, negative feedback loops exist to promote cohesion among players. Imagine an example, where every time you score a point in a game you have to pass your turn to another player. This system would favour people not scoring as many points as you and subtract from your advantage gained by scoring a point. Negative is not equivalent with bad here, but it relates to the idea of subtracting something. Your variable gain is turned into a loss. The blue shell (see video below) in Mario Kart games is a very well-known item that facilitates a negative feedback loop. In general, in Mario Kart, many higher power items only become available to you when you are behind in the race and if you use them well, they can help you balance out the game and catch up to the other players. In board games or turn-based digital games it can also be used to balance out the first move advantage (see other video below). Player-system relationships are balanced out by a negative feedback loop.(source:gamecareerguide)