Currencies in game economy loops

*featured on Gamasutra here

Wouldn’t it be helpful to bring more knowledge from simple visualizations into your game? After you’ve finished celebrating your game’s fun core loop, you’re probably examining adding upgrades, buffs and other unlocks in the game economy. Your game doesn’t need to involve stocks or inflation to have a game economy. Game economies aren’t just the total gold earned, they include everything from bullets left behind on the battlefield to an NPC’s opinion of you after a botched dialog situation. How do you visualize these sinks and sources that control these different types of game currencies to gate developed content? Let’s review high level currencies in your core loop diagrams and resources that help when building full system simulations of your own projects.

Core loop diagrams enable developers to quickly and visually break down what players do in a segment of the game. For instance, you might note that players battle an opponent, and then return to the upgrade screen to increase their damage and then loop back to battle again. You might document a loop where player’s hit start, beat a level, optionally share their score, and then return to the next level. Daniel Cook has the greatest backlog of conversations about core loops and arc diagrams on the web over at Lost Garden. If you’re looking for breakdown examples, check out Michail Katkoff’s mobile loop analysis at Deconstructor of Fun. Now that you’re familiar with the basics (or more!) of loop diagrams, let’s take a look at what adding high level currencies looks like in a flow diagram. Before jumping into complicated loops in games, let’s just add currencies to a simple diagram of making tea:
making tea loopsThe above is not too far off from what we’ve seen for traditional game loop diagrams, but note the standout text in green and red. Green marks currencies that our being added to our economy (called sources) and red marks currencies that are shrinking (called sinks). Just by adding those quick annotations, we have an instant understanding of the high level sources and sinks in this experience. I tend to use ++ or — to label “larger change” and + or – to label “less change”, these are qualitative not quantitative results because we can’t predict how many loops player’s go through, but they do note contextual relationships well. Even with just those loose annotations, we can instantly peek into the experience. For instance, there’s a lot of heat involved earlier in the process, with none later. We can see as time passes when we let our tea sit, the taste of the tea increases as the heat goes down.

Since most folks can access free mobile examples (and we’re all secretly excited for more lightsabers) let’s open up EA’s recent hit, Star Wars Galaxy of Hero’s as a first example. Using this blog’s introduction of upgrades, progression, and gates, let’s observe how SWGoH (Star Wars Galaxy of Hero’s) provides those elements. SWGoH has you completing battles in order to provide your party with upgrades and offers “sims” to instantly complete and get loot from completed battles. Powerful upgrades have different chances of being obtained upon the success of specific battles. Side stepping a different blog about this model made famous by Hero’s Charge, let’s diagram a loop in regards to entering battles to progress in the game:


In addition to energy, this loop sinks both crystals and sims while providing a widely accepted experience for players to get their fast tracked upgrades from simulating playing past content. It also avoids burning out players with repetitive grinds. This spend continues to be valuable from early to late game, providing content with self worth that keeps the inflation of soft currency down with a simple sink. These sinks tie directly into the core progression loop of ranking up characters to complete harder and more rewarding battles. Inside this core loop, we quickly trace optimal and alternative paths for gaining currencies and where these currencies are sunk away. Using ++ and — with + and – we get a good sence of “more or less, best or worse paths” but we can take these insights a step further with more advanced modeling.

While it does have limits, the flash based Machinations by your soon-to-be-idol Joris Dormans is a tool that allows these types of game economies to be simulated and interactable. I highly recommend poking around the Machinations Wiki and running through some examples, I recommend Advanced Game Mechanics by Dormans and Adams if you’re really hungry. Unfortunately, the Machinations Wiki’s playable examples have become broken because the version of flash is no longer supported, but you can find an exhaustive backup of examples on the wiki or as plan B get them all here on These resources provide the best foundations for simulating game economies with Machinations and general game design:

Let’s take a look at a more traditional genre, the RPG. In an RPG economy, skills and buffs affect the player’s ability to perform specific types of tasks. In addition, player characters must perform tasks successfully to increase their abilities, embracing the positive loop, and having better chances with the next enemies. At a basic understanding, XP and character levels act as the main currencies. Take a look at this Machinations diagram:



To start, the dice shown icons below the HP, PP, and Mana labels check the chances of players successfully winning an attack against an enemy. These chances are influenced by the color coded difficulty in the bottom left that include slight random variations. When players successfully execute attacks upon those conditions, they flow into the XP pool near the bottom middle. Players choose when to convert this XP into an additional character level on the bottom right. This character level creates two upgrades which flow to the upper right and can be distributed into the HP, PP, or Mana skills. This embraces the classic RPG positive loop mentioned earlier as the player keeps fighting enemies and continues getting stronger from them. With a longer look at this high level diagram, can you already predict any potential issues with player progression?

– There are many potential answers! Perhaps you answered that question with one my top frustrations in RPG’s: Over-rewarding of player specialization. In the diagram above, and often in RPG’s or role based experiences, players are rewarded for hyper speciation of a set of skills that locks them into that role for the mid and endgame. What is players have picked a role that doesn’t have enough depth to match the game’s expanding content or simply want to change up their personal game experience? In the above, the optimal strategy would be to only upgrade one skill. Imagine if they only increased their health which could allow them to grind enemies (and complete the simulated higher difficulty dice rolls), but wouldn’t match the game’s goals of a good experience. Even at this lower level of game fidelity, we’ve identified a problem and can explore solutions. Perhaps we adjust this diagram to include a negative loop on certain upgrade costs or require abilities to be evenly upgraded? What solutions would you deem best?




We can use this tool to inform our economy and game balance sheets that import directly into the game. Using Machinations’s chart function, you can get an idea of how much gold a top player might be able to obtain or where a lower tiered player might have issues in your economy when trying to unlock new content. These estimates can better guide our initial playtesting or soft launch numbers, and some can even be plugged into your spreadsheet inputs for your game. Don’t forget that later in development, you can literally plug in your game’s real numbers of averages / highs / lows you gained from your Analytics into detailed simulations to quickly model a specific player’s experience. If you’re first starting out with analytics, find my “101” series of part 1 on terms here or part 2 on mistakes here, and the best bits and more summed up in my Unite 2015 Analytics talk here. All of these resources allow you to build a better mental model of how others experience your design.

I hope you have a better understanding of adding currencies into your diagrams and how to make them even more useful than before. I’m only scratching the surface of all this myself, but feel free to reach out over my twitter @tDJ where I discuss design regularly, and I can try to answer questions. Keep making great games, looking forward to playing them!


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