Every game has what I call a “surface area” for its gameplay systems. At a fundamental level, when we design progression systems we are deciding how we want to dole out access to that surface area as rewards.
So let’s talk about surface area in more depth!
An Illustration
Let’s look at this from a top-down perspective, first: game devs have an experiential goal and they need to solve towards that goal. We can start with a simple example: The Legend of Zelda (1986).
Drawing inspiration from RPGS like Ultima and Black Onyx, one of the major design goals for Zelda was to make the player character grow stronger over time. Some other goals were to make the game feel like hiking, and to make the game feel like an Indiana Jones-style treasure hunt. In service to those three goals, the game had 33 permanent upgrades that the player could find. Finding them required exploring the game world, and either navigating dangerous ruins or finding them hidden in the overworld. These upgrades were a mix of items that provided new gameplay abilities, upgrades that improved item stats, and heart containers that increased the character’s health.
Zelda 1’s Surface Area and Apportionment
The surface area of the original Zelda is pretty easy to define. We can think of it as the totality of everything the player can do. It’s similar conceptually to a game’s “possibility space”, but we’re defining and quantifying it from a different enough angle that I don’t want to use that term.
Let’s say that in this scenario*, the Zelda designers have defined the full surface area, and now they’re trying to figure out how to provide enough rewards to incentivize exploration and to create a sensation of growing power. They need a certain density and pacing to these moments to maintain player interest and create the emotional texture they want. So they land on the following:
| Surface Area | Apportionment |
| The player has a number of abilities | All upgrades and abilities come from finding discrete objects in the game world, or buying them from merchants |
| A sword attack that does 4 damage | 1. The player starts with no sword 2. Three separate swords can be found that do 1/2/4 damage respectively. |
| 16 Hearts of health | 1. The player starts with 3 hearts 2. 5 hearts can be found in the environment 3. 8 hearts are earned by defeating dungeon bosses 4. The player can find a Blue Ring that halves damage 5. The player can find a Red Ring that quarters damage |
| The player can block projectiles with their shield | 1. The player starts with a shield that can block only a subset of projectiles 2. The player can find a better shield that blocks more projectiles |
| A bomb that can be placed on the ground to do a time-delayed AOE attack. The player has a 16 bomb holding capacity | 1. The player starts with no bombs and an 8-bomb holding capacity 2. The player can find or purchase bombs 3. Bomb capacity can be upgraded to 12 or 16 |
| A boomerang projectile that rapidly flies to the edge of the screen and returns | 1. The player starts with no boomerang 2. The player can find a Boomerang that has a slow projectile speed and a short range. 3. The player can find a Magic Boomerang that has a fast projectile speed and a long range |
| The player can spend a rupee to fire an arrow that does 4 damage | 1. The player cannot fire arrows initially 2. A Bow can be found that allows them to fire arrows that do 2 damage 3. Silver Arrows can be found that increase arrow damage to 4 |
| Unlimited flame projectiles that: – Fly across the screen – Damage enemies – Burn bushes – Light up dark rooms | 1. The player cannot fire flame projectiles 2. A Blue Candle can be found that can be used once per screen to fire a single short-range flame projectile 3. A Red Candle can be found that can be used an unlimited number of times to fire a single short-range flame projectile 4. A Magic Rod item can be found that allows the player to fire unlimited long-range projectiles, but does not burn bushes or light up rooms 5. A Magic Book can be found that upgrades the Magic Rod to fire unlimited long-range flame projectiles |
| The player can travel across bodies of water at docks | 1. The player cannot travel across bodies of water 2. A Raft item can be found that allows the player to travel across bodies of water |
| The player can freely walk across 1-tile gaps | 1. The player cannot move across 1-tile gaps 2. A Stepladder item can be found that allows the player to freely move across 1-tile gaps. |
| (And more!) | |
*This is definitely not the way that the Zelda 1 team designed their game, so consider this an illustration only.
As you find all the upgrades your capabilities go from fairly limited to very powerful. Your health increased. Your armor and damage increased. You got ranged weapons, AOE weapons, items that let you cross oceans or holes. By the end you are the master of that sandbox.
The Surface Area Problem™
Zelda 1 is a short game, generally 3-8 hours long depending on player skill and knowledge. What happens when you want to make an 8-20 hour game but maintain the same density of rewards and incentives? If you only have 33 permanent upgrades, they may feel too infrequent. Do you expand to have 65-70 permanent upgrades…? Does your game even have enough surface area for that?
What about when you’re making a massive modern game with even denser rewards, but you’re expected to make it last for hundreds of hours of play? Maybe it’s even a live service MMO-style game and you’re asked to provide endless rewards.
Ultimately there are several paths forward if you want to make your game longer while retaining the same density of rewards:
- Increase surface area
- Subdivide surface area more granularly
- Resetting progression
- Design a game that does not rely on progression rewards to drive interest
- Design short games
Solving or mitigating this problem is one of the main functions of the “system designer” job at many modern studios, but these are such foundational elements that it needs to be considered at the pre-production stage and at the directorial level.
Options #4 and #5 mostly just dodge the issue. But those options are not always available, especially on big budget games at large studios. Option #3 is what Roguelikes, Diablo seasons, and even some arcade games use, and it allows them to reset and re-use the same progression elements over and over.
But let’s say you want to make a fairly traditional progression-driven game, like an RPG or a single-player game with a campaign that has permanent mechanical progression. Let’s dig into options #1-2.
Increasing Surface Area
There are many ways to increase a game’s surface area, but it can mostly be summed up as “more to do”, “more options”, or “pushing boundaries.”
If your main game is action, you can add stealth missions. If your game has melee combat, add ranged combat. If the last game’s turn-based battles were just trading damage, maybe the second one adds dimensions like status effects, hard resistances, hard counters, and aggro management. If in the last game your party had a single character you needed to equip, maybe in the next game you have 4 party members.
Maybe you add a recurring minigame like The Witcher 3’s Gwent, Final Fantasy 8’s Triple Triad, or Trails of Cold Steel’s fishing game. Or even a housing system, where players can purchase, upgrade, and decorate a home.
All of these options allow you to give out more rewards. Skills that are useful for stealth. New cards for Gwent. A better fishing pole for the fishing minigame. More party members means more gear to equip. More dimensions in combat add more potential for skills, items, and other verbs. Housing systems of course call for furniture and decoration!
The main experiential downsides of increasing surface area is that you usually also increase complexity and mental load, so it’s easier for your game to feel overwhelming. You will also find it harder to make all parts of your game appeal to all your players. If you’re relying on a housing system to provide meaningful rewards, the player who loves the rest of your game but doesn’t care about decorating their house may value rewards less.
The main production downside of increasing surface area is that it requires increasing scope! Someone’s gotta design, plan, build, and test all this stuff, and then deal with the organizational complexity of features that all need resources and may have contradictory goals and needs.
Subdividing Surface Area
There are basically two ways to go about subdividing a game’s surface area: increasing granularity, or building systems of indirection between the rewards and the progression.
Increasing Granularity
Earlier for Zelda 1 I described “apportioning” the surface area; this was mostly done by increasing granularity. Instead of starting the player off with a sword that does 4 damage, the player had to acquire three upgrades before they could do 4 damage. Instead of starting off with maximum damage resistance and health, the player had to find 13 health upgrades and 2 armor upgrades.
Any time that we are taking the same surface area and splitting it up to dole it out to the player in smaller chunks we are increasing granularity.
Increasing granularity is often the cheapest way to subdivide a game’s surface area. It’s dangerous to over-rely on this method though. For rewards to truly work, players need to perceive their benefit, and need to value them. If we subdivide too much then we risk individual rewards becoming imperceptible, and rewards cease to fulfill their function.
Everyone can immediately feel a huge difference when they get a sword upgrade in The Legend of Zelda: enemies that used to take two hits to kill now take only one! The clarity and elation of that power growth can be lost.
Systems of Indirection
In this context, a system of indirection is a middle-man system that sits between rewards and progression, and allows us to break the 1-to-1 connection between earning something and getting access to more surface area. The classic example is currency. If treasure chests reward 200g, and you need to spend 1000g to buy that next sword upgrade, that means that we’re getting 5 rewards to place in the game world out of a single chunk of surface area.
In that example the currency, the treasure chests, and the vendor that sells you the sword are all part of a system of indirection.
A more advanced version of this might be something like Monster Hunter Wild’s crafting system, which involves hundreds of possible currencies, which may come from different sources or different achievements all throughout the game. It creates a complex web of goals, rewards, and progression.
Random loot is also a system of indirection. It’s the difference between opening a chest and getting a sword upgrade vs only having a 10% chance of getting a sword upgrade from the chest.
If you want to see this tactic taken to its utmost, take a look at free-to-play gacha games: they liberally use many layers of indirection to purposefully obfuscate the line between achievement and reward, and between real and imaginary money.
These methods are powerful but if not handled carefully can suffer from the downsides of the other methods. They typically increase production scope and mental load on the player, and they can also make rewards feel less impactful because their impact is too obscured.
Using this lens in development
I think this way of looking at a game’s systems and rewards is powerful and useful for analysis, but will typically not be something system designers are thinking about day-to-day. It’s useful for diagnosing problems and for very high-level or early planning: creative direction and pre-production decisions. I think many modern games and genres have immense pressure to provide as many hours of entertainment as possible, and to maintain player engagement over long stretches of time. These pressures push game devs to increase surface area, subdivide surface area more, and add increasingly complex layers of indirection. Understanding the interplay between these things, and the experiential and production dangers they bring, can be extremely important.
I hope this provides some of you with a useful tool as you design these kind of progression experiences!