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The Future of Game Design:
Moving Beyond Deus Ex and Other Dated Paradigms

by Harvey Smith

Abstract

As an art form, immersive games are in a transitional state, currently positioned on the cusp of something almost unrecognizably different. Future games will employ deeper simulation in order to achieve far greater levels of interaction and complexity, while simultaneously simplifying the learning curve for new players. Most game environments of the past have been based on crude abstractions of reality, limiting player expression and requiring users to learn a completely new vernacular in order to play. The games of the future will rely heavily on much more complex, high fidelity world representations that will allow for more emergent behavior and unforeseen player interactions. Taken together, these next-generation design paradigms are not simply improvements over older models, but represent a fundamentally different approach to simulating real-world physics, handling artificial intelligence and interface usability.


Using the award winning and critically acclaimed game Deus Ex as an experimental foundation for discussion of these new design paradigms, come explore the theories that will bring about the renaissance of the next-generation of interactive exploration.

(This lecture was first presented as the keynote address of the game track at the Multimedia International Market, in Montreal, October 2001)

 

I - DX and Me

Hello. I'm Harvey Smith from Ion Storm Austin, an Eidos studio. I was lead designer of Deus Ex and I'm project director of Deus Ex 2. This is intended as a lecture concerning the ways in which increasingly complex simulations will lead to richer gameplay environments in the near future. This is my first trip to Canada and the first time I've attended the MIM conference. I'm glad to be here. Prior to working for Ion, I worked at two other game companies: Multitude, where I was lead designer of a game called FireTeam, and Origin Systems, where I worked on several games in a variety of roles. I started in the game industry as a quality assurance tester in 1993.


Deus Ex, the game our studio finished last year, was a hybrid game that attempted to create an environment in which the player was calling the shots as much as possible. The game mixed a variety of genre elements, including:


Deus Ex tried to provide the player with a host of player-expression tools and then turn him loose in an immersive, atmospheric environment. We wanted to do this in a way that did not limit the player to a few predefined choices, but instead allowed the player to come up with his own strategies within the flexible rules of the environment. We wanted to allow the player to approach the game from the direction of his choice, employing his own play-style cobbled together from the options we allowed. Sometimes we succeeded; sometimes we fell back on more traditional (more limited) means of providing interactivity. The desire to give this talk today was largely fueled by seeing both moments in Deus Ex.


When we did succeed in implementing gameplay in ways that allowed the player a greater degree of freedom, players did things that surprised us. For instance, some clever players figured out that they could attach a proximity mine to the wall and hop up onto it (because it was physically solid and therefore became a small ledge, essentially). So then these players would attach a second mine a bit higher, hop up onto the prox mine, reach back and remove the first proximity mine, replace it higher on the wall, hop up one step higher, and then repeat, thus climbing any wall in the game, escaping our carefully predefined boundaries. This is obviously a case where - had we known beforehand about the ways in which these tools could be exploited - we might have capped the height or something. Most of the other surprise examples I'll mention today are going to be 'desirable' examples of emergence or emergent strategy. But I thought I'd start with an undesirable example because that's one of the things you have to watch for in attempting to create flexible game systems that behave according to implicit, rather than explicit rules. In any case, we were delighted at the flexibility of the system, of the ingenuity of the players and of the way that the game could, in some ways, be played according to the player's desires, not the designers'.


When we failed in our attempt to implement gameplay according to our lofty goals and instead fell back on some special case design, players sometimes felt robbed if their actions caused a situation to 'break' or if we failed to account for some desired play-style. For instance, many times we included three paths through a map and each corresponded heavily to a play-style like stealth, combat or high-tech hacking. If a player typically resorted to some other play-style (like seeking out water passages and using SCUBA gear to get past obstacles), then that player acutely felt the limitations of what we had offered. Instead of feeling like he was operating within a flexible simulation with consistent rules, suddenly the player felt as if he needed to figure out what the designer wanted - what the designer had explicitly planned as the 'right way' to negotiate a part of the game. This problem was even further exacerbated in the few cases where we provided only a single option. For instance, at one point in the game (for plot purposes), we wanted the player to set off a security alarm in one particular research lab complex. There was no way to avoid setting off this particular special case alarm, even for the player who had spent most of his in-game time and resources on playing as a counter-security specialist. Players felt completely robbed. This was a forced failure in Deus Ex, created by a special case break in the consistency of our game rules.


The success cases in Deus Ex tended to rely on the interaction of flexible sub-systems within the game (and were about what the player wanted to do). The moments that I perceive as failures tended to rely on special-case triggering or scripting (and were more about what the designer wanted the player to do). The experiences we had working on DX1 motivated us to move further toward more deeply simulated game environments. I'll return to Deus Ex off and on, but first let me briefly outline my talk.

 

III - Simulation Overview

A simulation is a representational model. Computer and video games have obviously simulated aspects of the real world (or some skewed version of it) from day one. Early on, most of the simulations involved were fairly simple. For instance, in Pitfall - the classic Atari 2600 game - the notion of gravity existed; if the player leaped, he moved up and forward, then fell, in a crude approximation of gravity. On the other hand, you could point to Lunar Lander (and a few other space games) as example in which a concept like gravity was modeled in much greater detail, accounting for planetary mass, directional thrust and momentum.


Modern examples of representational game systems abound, from crude models to overly complicated models. For instance, some first person perspective games have allowed the player to get into vehicles. In some of these cases, the vehicle physics simulation is too crude with regard to the way it interacts with the terrain, allowing the player to get stuck on small hills that it seems like the vehicle should be able to negotiate. On the opposite end of the simulation scale, Trespasser is probably a game that, despite any innovations or strengths it might have had, could be said to have failed because it featured overly complex simulations without the requisite control and feedback. So the vehicle stuck on a small bump is a symptom of a simulation that's too crude for the game; conversely, Trespasser's problems were a symptom of a simulation that was too complex for the game.


In the past, games have been mostly about branching paths. The designer manually sets up a number of outcomes or interactions and allows the player to pick one. This merely equates to a handful of canned solutions to a particular game problem. (Some hypertext writings refer to this as "multilinear," or allowing simultaneously for multiple linear options of equal value.) Deus Ex featured some options for player expression that were facilitated by systems of coarser granularity. (Good examples here might include our branching conversation system or a critical room that could be entered at only three specific spots, each representing a different approach.) Manually setting up solutions to game problems requires a lot of work on the part of the team, can result in inconsistencies and generally only equates to a small number of possibilities for the player. However, Deus Ex also featured options for player expression that were facilitated by systems of finer granularity. (Good examples might include some of the player-tools that we provided that were tied into analogue systems like lighting or sound, such as the ability to see through walls or dampen the sound of movement. These tools interacted with our enemy awareness models in numerous, fairly complex ways. They could be activated at any time in a very wide range of situations, incorporating distance, facing, enemy type, etc.) The finer-granularity systems required more feedback and introduced some uncertainty that equated to some interesting degenerative exploits; but the freedom players felt more than made up for these costs.


Essentially, almost all games involve representational models of reality. So why talk about simulation? What's happening is that the models are becoming finer in granularity. We're talking about a scale here, with incrementally more weight being added to the sim side. We're slowly moving toward games built upon much higher fidelity conceptual models, with greater control or self-expression. At some point, the scale will tip. There will come a point (in part, an arbitrary point) at which gameplay in the average game will be much richer because the player will be presented with a vastly larger range of expressions. Yes, we're moving incrementally along, but at a certain point, the systems become flexible enough to allow for emergence, at which point the experience is more about the player's desires.


Example list of slow progress metrics toward more complex simulation:


This brings up the question: Why should we continue to attempt to build games around higher fidelity simulations? Why is a wider range of expression better? Multiple reasons:


There are also a couple of side effects of setting out with the goal of creating games around deeper simulations:

 

IV Game Simulation - Specific Systems

I've talked some about specific systems in passing - Thief's sound propagation and lighting, for instance. Now let's get more specific:


Sound/Light and Unit Awareness:

Many games model 'enemy awareness' in some way, attempting to simulate the real-time gathering of information. In most combat games, for instance, enemies perceive hostile or suspicious events. I think we're at a point where traditional models for perception are just not enough - relying on such models is having an increasingly negative impact on overall gameplay.


For instance, in DX1, sound propagation worked like this: A sound event was broadcast in a sphere outward from a source, ignoring wall/floor surfaces (as if the sound were generated in an empty space). Taking distance into account, units within the broadcast would be alerted (i.e., would 'perceive' the sound). A different model was used to determine whether or not to play a sound for the player (involving a line-of-sight check to fake dampening a sound if it was playing through a door, for instance).


By contrast, let's look at our plan for sound propagation in DX2 (which we think is the next step in the direction undertaken by Thief): A sound event is broadcast in a sphere outward from a source. In cases where the sound hits a surface, we bounce the sound, taking into account the material applied to the surface. (So that carpet muffles the sound, for instance.) The number of bounces is capped. Taking distance into account, units 'perceive' the sound if the sound reaches them, directly or by bounce. The same model is used for both player and game unit (or guard) to determine whether the sound is perceptible. Certain acoustic aesthetic effects are ignored on the AI side, but these have nothing to do with whether the AI perceives the sound.


The first model (the one used by DX1) did not always allow the player to predict whether a game unit (like a guard) would hear a sound or not, which led to some really unsatisfying occurrences: Either a guard would hear the player (when the player assumed that he was acting 'quietly'), or the player would make sound that he assumed a guard should hear (but the guard wouldn't, making the game's awareness model feel broken). We think the second model (the one being used for Thief3 and DX2) has the following benefits: We can unify player-related and enemy-related sound propagation, which will allow for a more intuitive game environment. The player will be able to make assumptions about whether a guard will hear him or not based on the player's own perception of sounds in the environment. We also hope that the higher fidelity model will equate to a more 'fair' gameplay model; guards will not hear sounds that are blocked by multiple thick walls. (Again, this will allow the player to make some strategic assumptions, closing a vault door before operating a noisy tool, for instance.)


Anecdotally, I want to mention that DX1 players already do things like closing doors before taking actions (because that is the intuitive thing to do - something we learn from childhood forward, trying to trick our parents and siblings). If players do this, but realize that the system does not take something like a closed door into account, they feel cheated or let down. If they're going to do it anyway, it makes some sense to model the game according to their intuition and assumptions; we don't want to pass up the chance to squeeze in an interesting, intuitive game dynamic. (This is a good example of a deeper simulation leading directly to more player expression, more gameplay.)


Realistic Physics:

Currently physics is useful for establishing player-action capabilities - limitations related to movement speed, falling damage, gravity, etc. But over the last few years moving toward more realistic physics has had other significant gameplay ramifications as well.


First, a comment about the word "realistic":

In games, realism is not necessarily the goal. But if the world seems to behave consistently and in ways that the player understands, it seems that the player has less difficulty immersing himself in the environment, suspending his disbelief. In this way, realism in games is related to intuitiveness and player expectation. (It's also worth noting that if you set up an environment that seems familiar (and thus is intuitive) then you thwart the player's expectation of that environment, the player often finds it extremely jarring. For instance, we included telephones in Deus Ex and gave them limited functionality. Their presence helped the player identify, say, an office space as a familiar, real-world location. However, we could not possibly make the phone in the game as flexible and powerful as a real-world phone is, and the lack of functionality in the game-phones served to immediately remind the player that the office space was "fake." It might have been better to leave the phones out altogether. So realism is not the point (even though it can be useful).


Continuing with "realistic physics": The first game I played that allowed me to realistically bounce grenades around corners was System Shock. Bouncing grenades around corners is an example of "physics as gameplay." It's one step less direct: Instead of going toe-to-toe with an enemy, the player can take up a safer (more strategic) vantage before attacking. The player suddenly had new, interesting options. It also makes the environment more dynamic: If someone moves a crate out into the center of the room, a grenade can then be bounced off the crate. Obviously, collision physics that allow for grenade bouncing gameplay have been around for a while. But the more thorough and more realistic physics simulations of the next generation of games should have interesting ramifications. To cite some examples:


General Game Systems: Tools and Objects

In the past, gameplay tools (including weapons) had to have explicit relationships with any other elements of the game in order to affect those elements. So a weapon class, for instance, specifically contained code listing all the things it could affect. For instance, to use a simplistic example, if you wanted the bullets from a gun to break a window, you had to set up a direct relationship between the weapon entity and the glass entity. Now, there's an additional layer of abstraction between the two: The weapon projects a bullet entity. The bullet entity carries with it information about what properties it carries (like ballistic damage, heat or electricity, for instance) and the glass is a stimulus-receiving entity. When the bullet meets the glass, the game's object/property system looks up the effect of the bullet's properties on the glass entity. There is a set of rules about the relationships between these general-case properties.


How is this different, from a pragmatic standpoint? The latter, more flexible approach (with the layer of abstraction between the bullet and glass game elements) has the following benefits:


It's largely due to hardware limitations and the nascent state of interactive entertainment that games have by necessity relied on cruder models in the past. No single game project of which I've been a part, including Deus Ex, has fully taken advantage of all the opportunities to provide the player with as much exploration and expression as possible. With that qualifier, I will relate the following example:

Recently at one of the game industry's conferences, I had an opportunity to see the demo for an upcoming game. I've been excited by this game for quite a while. It's essentially an adventure or role-playing game that allows the player to explore a fictional world, building up his power so that he can face increasingly tough threats, while uncovering new pages of the game's plot. This is a traditional conceptual model, but a popular one that has provided a lot of enjoyment over the years. This new game looks and sounds beautiful; I fully expect it to be a lot of fun. (I'll be buying it…) But after talking to one of the developers and watching him play the game, I cannot help but point out how I think that the designers have missed some opportunities. The game seems to feature an extensive set of player tools and powers. However, most of them are purely related to inflicting damage. The rest of the environment is modeled in a very simple way. The game uses a traditional paper RPG-style 'spell' system, which should allow for a great number of interesting player expressions, even if you restrict your thinking to the tactical arena. So, during the demo, I inquired about types of spells that, in paper RPG's, are often exploited in interesting ways beyond toe-to-toe combat. For instance: Can the player freeze the water pool (in the cave featured as part of the demo) as a way of creating an alternate path around an enemy? Can the player levitate a lightweight enemy up off the ground and thus get by it without resorting to violence? Can the player take the form of a harmless ambient animal and sneak past the goblin? Can the player create fake sound-generating entities that distract the enemy? I believe the answer to all these questions is "no." The game was designed around pre-planned, emulated relationships between objects. Had the game been designed around a more flexible simulation, these sorts of interactions might have just worked, even if they had never occurred to the designers. (All of this still might be possible in the special case emulation model, but would run the risk of a great deal of inconsistency, would require tons of work and would not as likely produce emergent results.) Had the game been built around more thoroughly simulated game systems, creating more interesting (less combat-centric) tools would have been easier - the game's possibility space would have been greatly enlarged.


By contrast, let's look at the gameplay tools given to the player for the game System Shock 2 (by Irrational Games and Looking Glass Technologies). There was a web post about a player who, when under attack (by a mutant and a turret) and completely out of ammo, used psi-telekinesis power to pull an explosive barrel toward him, moving it through the firing arc of an attacking turret. The turret blew up the barrel, destroying the turret and killing the mutant. No one on the System Shock 2 development team explicitly set this area up with this outcome in mind; these things emerged from the game's general-purpose approach to gameplay tools interacting with the other elements at the whim of this (clever) player. This is a really good example of a flexible, consistent set of rules, very similar to our bullet/glass or collectible card game examples from earlier: Rules about the relationships between the game's objects and tools had been established at a high level. No code or scripting specifically related to the idea that the player's psi-telekinesis could pull barrels in front of turrets; instead the psi-telekinesis was set up to affect moveable objects, the barrel was tagged as a moveable object, the turret projectiles were set up to affect explosive objects and the barrel was set up as an explosive object. And everything just worked.


Again, as a downside, in attempting to create flexible game systems (that behave according to implicit, rather than explicit rules) problems are caused by undesirable exploits. So efforts must be undertaken to bulletproof against anything that outright breaks the game.


Unit Needs and Behaviors

Most game units have very limited awareness of their state, needs or environment. They generally don't need any greater awareness: Imagine a racing game in which one of the drivers was distraught or suicidal because his Sim-girlfriend had just broken off their relationship. Sounds ridiculous. But imagine a racing model in which the drivers were intelligent agents who were aware of their car's current fuel needs. That sounds interesting (to me). And, to integrate some of what we've talked about, imagine that this self-driver then uses the game's thoroughly modeled aerodynamic system to 'draft' behind another racer to conserve fuel. For all I know, people making racing games might already be doing this - my point is that the deeper simulation in our hypothetical model provides a much larger possibility space. The self-aware driver provides a more interesting AI opponent and the wind-drag model allows the player to take more strategic elements into account and act upon them.


The deeper simulation of additional aspects of a game does not inherently make the game more fun. But if you choose the 'right' aspect to simulate, you can make the game more interesting. For instance, DX combat featured units that would run away if they realized they were badly wounded. This did not make combat more fun, but it made it one step more interesting than a toe-to-toe shootout. Players remarked at how it prompted ethical decisions: Track him down and shoot him in the back, or let him go, since he is no longer a threat? For DX2, we're thinking of ways of expanding upon this idea, allowing units within a group to maintain awareness of group needs as well as individual needs. These leads to some obvious ideas: A medic squad member, a commander, etc.


Another direction in which we're trying to move for DX2 is real-time IK-based movement. People talk a lot about it, but we want to use it for gameplay-specific purposes. With IK pointing, touching and head movement, suddenly character movement is not limited to what an artist has pre-defined. With IK, we can model more on the unit's response-to-environment side. The IK will let a unit flexibly act on its desires. For instance, if a bystander thinks that the left door is the one that the police should open, it can point in real-time to the left door. (While not a needs-based behavior, the IK facilitates expression of this behavior. The IK 'body language' communicates AI state and change to the player.)

 

V - And Beyond

What comes next? Clearly we're moving along a curve of greater hardware capability, more elaborate software systems and a more sophisticated understanding of our nascent art form. What's the next revolutionary gameplay angle someone will exploit by figuring out a deeper, more interesting way to model a game system? I can't say with certainty, of course. But I can look at the last cycle of games and point to two interesting, noteworthy examples:


Someone in the next cycle, I hope, will pick out a new area, model it in a high-fidelity way that can be made interesting for the player, and will contribute their own part to the revolution. Maybe they will leapfrog from Thief's sound/light/awareness simulation in another stealth game, or maybe they'll pick up where The Sims left off and create characters that seem remarkably alive, with feelings, moods and relationships.


But what lies beyond the short-term? (This part is for fun - something to embarrass me in the future, like an insulting note from my past self.) How will games be different a decade from now? Here's some hopeful and perhaps provocative speculation:

 

VI - Summation

This wraps up the lecture. I hope you enjoyed listening as much I enjoyed preparing. Actually, I hope you enjoyed listening a great deal more than I enjoyed preparing.


As games continue to rely on increasingly realistic or complex simulations, obviously we'll have a bunch of problems to solve related to uncertainty and user feedback. But the end result, if we solve those problems, will be unprecedented possibility in games. Striving for finer granularity in the representational systems we create for games should allow players much more freedom of expression and should make the 'game' experience more about the player and less about the designer. We want players evaluating their environments, considering their tools and formulating their own strategies with as little regard as possible for what we as designers might have wanted them to do. Older game genres might be completely reinvented when built upon deeper simulations. Additionally, new game forms will emerge. Even though this approach involves the designer surrendering some control of the game's emergent narrative to the player, ultimately this should prove much more creatively satisfying; our goal is to entertain, to allow players to interact and express. In the future, we might only be "designing" games at a higher level, establishing parameters and allowing the players and the game's intelligent agents to work out the details.


Lastly, before I stop talking, I'd like to offer special thanks to the people who have taught me what I know about design and development, without whom Deus Ex would never have been made: Doug Church, Warren Spector, Marc LeBlanc and everyone at Looking Glass and Ion Storm Austin. Thank you and goodbye.

 

Author Bio

Harvey Smith is Project Director of the Deus Ex 2 team at the award-winning game studio ION Storm Austin. Recently, he worked as Lead Designer of the genre-bending game Deus Ex, winner of numerous Game of the Year awards, as well as the 2000 BAFTA for Interactive Achievement. Harvey, along with Warren Spector, was awarded the 2001 Game Developers Choice Award for Excellence in Game Design. Previously, he worked at Multitude on FireTeam, a team game that allowed players to co-operate using real-time voice over the Internet. Prior to Multitude, Harvey worked at Origin Systems in roles ranging from Lead Tester to Producer on several ambitious game projects. He is a member of the Advisory Board for Game Developer Magazine. Beyond video games, Harvey's interests include comics, dogs and writing. He lives in Austin, Texas.

 

The opinions expressed in this article do not necessarily represent the IGDA.