The following blog post, unless otherwise noted, was written by a member of Gamasutras community.

The thoughts and opinions expressed are those of the writer and not Gamasutra or its parent company.

I keep writing about "deep gameplay" and how it needs "complex verbs", i.e. mechanisms that go beyond probabilities, progress bars and damage numbers. But how exactly do those systems work then? This article will explore one possible answer to this question: space.

Goodbye math!

Gameplay can get strategically interesting when you cannot "simply" calculate everything, i.e. when factors are involved that cannot, or at least not easily, be turned into some kind of "points" or "score". If that would be possible, you would basically be facing a math puzzle. Of course that might be interesting in itself, but rather in terms of computing the correct solution and not so much in terms of intuition and decision-making.

Should the latter elements be supposed to be the game's core, offering strong spatial interactions can go a long way in moving it away from "flat" arithmetic. Positioning and movement in space or even aspects such as momentum or inertia are essentially complex resources that can, quite literally, be "played with". Obviously they are ultimately based on math as well, but a form of math that is both more complex than mere subtraction and yet also intuitively accessible for human beings.

Enter emergence!

This base complexity can furthermore be used to foster an emergent interplay between gameplay elements and thereby create even more depth without having to resort to more and more convoluted math. Of course the verbs in the game, i.e. the actions players are able to perform, have to be tightly connected to the game's spatial structure, so they can properly support it and give it meaning. Dealing damage, filling bars or the much-loved mass extermination of actors in the game world usually do not belong in this category. The same goes for mere asset tourism.

The following sections will take a look at some concrete examples on how to do it better. The games described below offer strongly spatial possibilities of interaction and consistently manage to align the design of all gameplay elements in support of this aspect.

Heat Signature: Moving through space...ships

In Heat Signature you enter procedurally generated spaceships and, by making use of a diverse set of gadgets, try to reach a specific target object or person. Almost everything in the game is centered on movement. For example, there are multiple types of teleport gadgets that e.g. allow you to swap positions with an enemy ("Swapper"), to instantly move through open corridors and doors ("Sidewinder"), or to jump to any position within a certain radius for a short amount of time ("Visitor"). The "Key Cloner" lets you steal key cards if the guard carrying them is in range. Luring enemies into the "Glitch Trap" will move them to another spot, often directly into outer space. And the "Slipstream" makes everyone act super slowly - except for yourself. More agility, more options.

These are just a few examples of the verbs in the game but one thing is pretty clear already: There is no flat number crunching. Enemies, just like your avatar, do not have "health points" or "stats" and do not "deal damage". The focus of the game lies on finding creative ways to bypass them or, if needed, take them out unnoticed in one hit. Most of the time you will not have a huge arsenal of weapons to achieve this. Hence one of the simplest tricks in the game is to let an enemy fire a bullet at you and then swap positions with him. A tactical option enabled by consistent rules and spatially meaningful verbs. Emergence.

Situations in the game can quickly get much more complex though. Therefore you always have the ability to pause the game, analyze what is going on, plan your next steps and even execute the first one of those directly from the pause menu. However, that will not make things super easy. It is just another design decision making perfect sense in the context of the core game and its depth. Players are supposed to plan ahead and think about which actions make sense in a given situation, instead of merely being challenged by their physical execution.

Spelunky: Up and (mostly) down

Spelunky is a modern classic and regarded as a game design masterpiece. Rightfully so, since basically all the elements in the game are tailored to interact with moving around its incredibly hostile environment. It starts with the two basic items: Bombs allow you to reach sealed off areas or create new connections. Ropes can be used to move upwards, which goes against the natural gravity-based direction the game usually takes. The same is true for climbing gloves and the iconic jetpack that additionally increases your horizontal reach. Jumping boots increase your jumping height. The mattock can manipulate a level's layout. Spike shoes prevent you from sliding over ice blocks.

But it is not just the items. The behavior of each enemy and every trap in the game has an immediate spatial impact and frequently forces you to reconsider how to move forward. You cannot land on spikes or stand next to a tiki trap for too long. Boulders need to be dodged. Arrow traps can be triggered by throwing rocks or other objects into their line of sight. Crush traps try to, well, crush you in a straight line. Spiders jump around, bats can fly. Tiki men throw boomerangs that return to them on the same path. Mummies vomit poison that can make a whole corridor impassable. And so on.

Again, all these elements are spatially meaningful and follow clearly defined rules that can then be combined in all kinds of ways to generate a large variety of interesting situations and confront players with new challenges. Therefore it makes perfect sense that the procedural level generation is often praised as one of Spelunky's greatest achievements.

Invisible Inc.: Knowledge is power

At first sight, Invisible Inc. and XCOM have a lot in common. You take turns, leading a squad of characters with certain specializations through a grid of square tiles. But that is basically it. Where XCOM goes on to rely on hit probabilities and rolling damage numbers, Klei Entertainment's title focuses much more on dynamics and level layouts.

Once again, enemies in Invisible Inc. have no hit points and lethal weapons are not only extremely rare, but also punish players by increasing the alarm level on every kill. Typically you will only use them in cases of emergency and try to deal with patrolling enemies in another way. The simplest of which is to knock them out temporarily. However they then remain an active and spatially relevant element of the game world because they will wake up a couple turns later and furiously search their surroundings. Hopefully you took some precautions in the meantime!

In general traversing the levels of the game is based a lot on collecting information about the layout itself. Where are the cameras? Where can I catch enemies unprepared? Where should I place a trap? Which devices can I hack to increase my mobility? The alarm timer will also keep ticking up without you killing anyone. It pushes you forward and away from playing for safety. The game rewards clever, yet often risky maneuvers of efficient exploration. Of course the positioning of your units does play a role in XCOM as well, but one that is quickly reduced to mere arithmetic.

Card Games: A spectrum of spatiality

Other comparisons can be drawn within the realm of card games. Gwent for example has been hunting the holy grail of "row identity" for a long time now, trying to give the different rows on its battlefield as much meaning as possible. (By the way, this was a core design pillar of Crimson Company and also the recently released Artifact.) This aspect had taken a backseat during the game's development in beta, where in most cases it didn't really matter where you put a card on the board. With the recent full launch entitled "Project Homecoming" the team tried to put an emphasis on positioning again, e.g. by introducing effects that depend on which row a card is played on and by reducing the number of rows from 3 to 2, thus making the resource "space" more scarce.

The battlefield can get quite crowded in Minion Masters, too. However by making use of continuous space and real-time, it can go even further. Not only does the positioning of units matter when you play them, but also their autonomous behavior once they are in play. They follow very specific rules of movement. Some creatures are faster than others, some can fly past obstacles, some ignore certain enemies. The game quickly becomes a complex interplay of unit positions and mobility, always depending on the current state of the game.

Hearthstone does not have as much of a spatial structure: One row of up to 7 units, no movement. Compared to Magic: The Gathering though, the relative positioning of units can matter in some cases, e.g. when they buff adjacent targets. Prismata on the other hand refrains from using any kind of spatiality whatsoever. It simply arranges units and buildings on the screen in such a way that they can be easily perceived. Appropriately, it is the most mathematical of all mentioned examples, and arguably the least accessible.

And more...

Of course there are more examples worth discussing. The brilliant Portal is all about an unusual way of movement. Auro's design is a "clockwork" of spatial actions and abilities. The battle royale genre (Fortnite) is based on restricting players' freedom of movement over time. And the core of every MOBA (League of Legends), i.e. pushing lanes, is a fundamentally spatial mechanic.

However, the overarching point should be clear by now: A design that is tightly focused on spatial interactions can quite easily lead to interesting gameplay situations, incentivize intuitive decision-making over hard mathematical solutions, and foster systemic emergence. Praise space!