‘Possibility Space’ is a familiar concept in game design that has always resonated with me when it comes to understanding how we interact with games spatially and mechanically. Essentially, the term refers to a visualisation of all possible moves and states within a defined game space; representing the full range of interactions and possible outcomes available to the player. A well-crafted possibility space therefore constrains a player’s actions, and within a range that they understand clearly. This may be through physical exploration of the boundaries of the space, or through gaining an understanding of the mechanics by exhausting all possible actions available.

An oft used example is the extremely small number of moves possible in Tic-Tac-Toe, versus the near-unlimited amount of player states available in a game of Chess. In both cases, the physical constraints of the space are relatively small, but the possible moves and states that can emerge vary dramatically depending on the rules governing the space.

Eric Zimmerman states that we can attempt to understand the concept of a possibility space both metaphorically and literally. In a metaphorical sense, we can view them as “an abstract decision space or conceptual space of possible meaning”; referring to the underlying systems of the game that dictate the actions available to the player. Exploring the concept literally as a 2D or 3D space, we can focus on the organisation of spatial elements that guide and constrain the player’s actions. Here we can attempt to understand the space of possibility narratively, considering the impact that these spatial features may have on creating meaning.

Will Wright was an early adopter of the term possibility space, and regularly referred to it in a similar way to the ‘metaphorical’ interpretation mentioned previously. However some designers have favoured the more literal approach of the concept; and in particular have been exploring its connection to narrative design.

“Games create ‘possibility spaces’, spaces that provide compelling problems within an overarching narrative, afford creative opportunities for dealing with problems and then respond to player choices with meaningful consequences” – Warren Spector

Warren Spector, acclaimed for his work in narrative design and character immersion at Looking Glass studios, supports the fact that spatial features have a strong impact on the creating the narrative space of possibility. We can effectively view an individual game space as a ‘physical’ narrative place that guides and constrains the player. Another ex-Looking Glass designer Randy Smith; has also often used the term possibility space in regards to narrative. Randy believes that the creation of “honest and believable stories out of the possibility space” is the key to engaging gameplay. He states that as humans we have an innate desire to witness to stories resolve, and that framing these key narrative points as possibility spaces is a compelling way to understand storytelling in games.



Imposing limitations on the player is a fundamental part of game design. However, the challenge arises in deciding where these limitations are implemented and how the story, world and mechanics support these limitations to provide internal consistency. Observing this in terms of the navigational space available to the player, I want to briefly look at a great example of how incorporating heavy spatial limitations can affect the level of interactivity in the environment.

When studying level design, it may be uncommon to analyse the use of space in the point-and-click adventure titles popular in the 1990s, yet that is exactly what engrossed the majority of my interest whilst playing through Jordan Mechner’s 1997 cult classic The Last Express. The ambitious adventure game plays out in a simulated real time fictional story of a 3 day train ride on the Orient Express in 1914, the last few days prior to the outbreak of World War I. Though there are countless things you can admire with this game, from the fantastic rotoscoped animation to the simulated real-time actions of the characters, I want to try and specifically concentrate on Mechner’s decision to use a train as a confined space of play, and how the scale of game space dictates the level of interactivity.


The Last Express had a huge budget for its time, and aside from the large amounts of money being poured into the unique rotoscoped animation process, the production and design team put a lot of effort into fleshing out the environment – just six train cars in this case. The result is that the train became an incredibly coherent and realised environment, with the all the characters on board from the passengers to the staff, established as convincing, distinct individuals. As the game evidences, putting all your resources into developing a smaller realised game space can allow for a more detailed, fleshed out environment with a believable level of interaction. In the case of The Last Express, it allows you to freely explore the train cars, engage in conversation with characters and observe your surroundings, actions which become context dependant due to the simulated real-time movement of the train and the behaviour of its passengers. Mechner is attempting to tell a non-linear story in a very small, controlled game environment, by taking the limited amount of objects and characters available and providing variable outcomes depending on the time the player chooses to interact with them. This encourages fleshing out small game spaces with mundane, seemingly irrelevant interaction points that serve a purpose only at a specific time in the game story.

 “I think of it as a non-linear experience in the most linear possible setting, that is, an express train” – Jordon Mechner

While The Last Express evidences that confined spaces seemingly favour adventure games, when trying to generalise the application of heavy spacial limitations in game design there’s clearly multiple things to consider. For example, smaller spaces may mean less room for emergent gameplay to emerge in such a small area, and even a heavily detailed small room in an adventure title could turn into a pixel hunt with a lack of player direction. On the other hand, open world titles pride themselves of level of freedom governed by the player, but it of course becomes increasingly difficult to decide what the player can and cannot interact with in relation to the design and technical limitations. An often referenced idea in exploring a heavily spatially constrained environment is Warren Spector’s One City Block RPG. Spector’s dream involves constructing a single city bloc,; a highly-detailed building simulating the lives of the people that live there and the objects that reside with in it. It’s an idea seemingly popular with designers; to create an inhabitable space rich with believable interactions that is supported by the consistency and constraints of the world and it’s underlying systems.


15 years on from The Last Express, its clever use of space is still just as inspiring. It remains a great example of using a highly constrained environment to implement believable mechanical constraints, by providing internal consistency and supporting the overall narrative.


Thirty Flights of Loving Analysis

(Note: Contains minor spoilers, intended for people that have played the game. If you haven’t yet played Brendon Chung’s 15 minute masterclass in narrative design, you can do so from his website!)

The narrative in Thirty Flights of Loving is embedded, pre-generated story content that is exposed to the player linearly. What makes the game so interesting and unique however, is how this content is presented.

The game presents an excellent example of a story being told via the game environment. With no dialogue or cut-scenes, every piece of information is communicated to the player visually, be this through objects on a table, posters on a wall or the clothes a character is wearing. In order for the player to notice at least a few of these details, and with an attempt to provide a vague idea of what’s actually going on, the game is incredibly linear. Putting the standard point A to point B corridor shooter to shame, TFOL primarily requires you to simply walk through the path it has laid out in front of you in order to progress the story. Even more unusual, is the way the game physically ‘jump-cuts’ you seamlessly from one scene to the next, in the same way a film would. Building upon these filmic influences, the jump-cuts can dramatically change the mood and tone of the present scene in an instant, simulating a fractured timeline; erratically jolting the player forwards and backwards through pieces of the story. Chung cleverly uses this method to expose the player only to scenes that are the build-up to or aftermath of a pivotal action sequence, of which are never actually shown. The scenes that are present work as an attempt to briefly inform the player of what has happened in these missing pieces of the story, requiring the player to piece together what they do know and, pleasingly, actually think about what is happening in the story in a broader sense.

One interesting point surrounding TFOL concerns the actual level of interactivity that the player governs within the game world, and how this is reflected in the narrative. The scattered interactive objects, such as weapons that can only be picked up but not used, have absolutely no impact on the outcome of the story. It’s a strictly linear playthrough with no immediately obvious goals or objectives; where the execution of the story will always be exactly the same. The purpose of the objects within the game world serve only to visually give context to the story. The choice and interaction with the environment, bar a few examples, simply means the player can halt the progression of the story by remaining in the current scene until they decided to proceed. Ultimately, the level of observation with the game world dictates the depth of story presented to the player.

TFOL is flourishing with risky yet rich design decisions, with Chung further expanding on how the medium can provide an engaging narrative experience.