A breakdown of Jesper Juul's classic text on rule structures and game design.
From You Have to Burn the Rope
It’s a sort of weird tradition with game academics to throw out an elaborate definition of what a game is when they’re doing a book like this. As the indie and experimental scene continues to grind apart any attempts to concretely hammer down the concept, accepting the definition in an article has more to do with the sake of argument than actually expecting it to universally work. Juul defines a game as, “A game is a rule-based system with a variable and quantifiable outcome, where different outcomes are assigned different values, the player exerts effort in order to influence the outcome, the player feels emotionally attached to the outcome, and the consequences of the activity are negotiable.” (36) As Juul notes in one of many large graphs, there are now dozens of things that could be broadly defined as a game, but his definition might better be termed as the definition of an ‘emergent game’. (44)
This is an ongoing argument in the gaming community. Clint Hocking’s advocates designing games where the information state is perfect for the player. He freely explains how the buddy system works in Far Cry 2 because in his game there really isn’t any such thing as a spoiler. You’re supposed to know everything that’s going on because unlike a progressive design, the player must have a fuller degree of control for an emergent experience. They should understand the consequence of their actions and what the machine is thinking. As Juul explains, “For emergence, the game is the whole of the sum of its parts.” (78)
Juul then broadly defines what constitutes an algorithmic process or game design rule. It must end after a certain number of steps. Each step must be precisely defined. It can have zero or more inputs, but it must have one or more outputs. It must also be effective. A cookbook, to give an example, is not an algorithm because of the imprecise measurements and moments. Unlike an abstract concept, “an algorithm can work because it requires no understanding of the domain and because it only reacts to very selected aspects of the world – the state system.” (63) A state system is just the game’s current status based on the rules, defined by having a beginning and being altered by input from the player. The location of your pieces on a board game at any given time, for example. The point is, “a rule includes a specification of what aspects of the game and game context are relevant to the rule.
The rules of relevance are a place where rules and narrative meet in that learning a game also means learning to ignore the purely decorative aspects of plot. This is part of the process of information reduction.” (63) This is also what a game designer refers to as ‘chunking’. The more a player becomes familiar with a game, the more they tune out the visuals and just focus on interacting with the rules. Juul cites Quake III as an example of this, pointing out that most hardcore players turn the detail level as low as possible to ensure the game runs quickly. They don’t care what the game looks like or is about anymore. (139)
From Quake III
The narrative sections of the book mostly dismiss progressive games and instead focus on the growing genres that merge the two design aesthetics. The book was written in 2005 and as a consequence Juul must focus on Grand Theft Auto III and The Sims for many of these points. As noted above, both games create a broad series of rules and choices that the player can make. This creates a game world, one whose visuals, sound, and interactions are all communicating a sense of space to the player. (163) The most crucial role of fiction is to cue the player into understanding the rules. (189) In order to ensure that the game remains interesting, the space must have a wide variety of different rules that do not overlap. He refers to this as ‘orthogonal unit differentiation’ or put much, much more simply: every unit has a strength and weakness. The key is to make sure there are a number of different non-overlapping axes that the units can be placed along rather than just one axis such as “strength”. (108) Doing one activity in two different contexts should be possible and should produce different outcomes. For example, doing a plot mission in GTA III produces an outcome different from if the player was just driving around smashing things, even if they are in the same location. These emergent systems present a fictional world, one the player accepts because the rules create an abstract and changing process. (170)
This eventually leads to the portions of the book that focus extensively on narrative. The problem for Juul is that if you’re willing to accept that a game is always functionally just an expression of its rules then you are not going to be able to create certain kinds of stories. He notes, “The goal has to be one that the player would conceivably want to attain….Superficially, it would seem that the player is only attached to the outcome on the level of the rules, and as such, it would be irrelevant whether the goal of the game is to commit suicide or to save the universe.” (161) Technically, there are several hilarious games that present just such a goal today. As a consequence, Juul points out that it would be difficult to make a tragic game because that conflicts with a player’s sense of the win-state. You could make the rules focus on achieving a tragic conclusion, but who would want to play such a thing? Juul writes, “While a clear valorization (goal) and emotional attachment to the outcome afford the player an opportunity to succeed, they also mean that the player can fail miserably.” (199)