When The Witcher 3 first came out,
in 2015, it didn’t take long for CD Projekt Red to realise that there was
a big problem with the game’s economy. You see, a few enterprising players figured
out that they could go to White Orchard, kill all the cows on the farm,
and sell their leather for cash. And then, if Geralt meditated to pass some
time… the cows would all come back to life. So, if you’ve got the patience, you could
repeat this simple process as many times as you want - and amass infinite wealth before
leaving the very first village in the game. Whoops. Look, video game economies can
be very complicated to design, with all sorts of room for imbalance
and exploits. But if you get it right, an economy can be a really powerful
tool. It can shape player behaviour, change the pace of progression, offer up
difficult choices, and create challenging puzzles. So, in this video I want to give you a
crash course in video game economy design. I’m going to map out a typical video game economy, by describing the five basic entities
in the system and the way they connect. And as we go, I’ll show you how the design
of the economy can change the way we play. Plus, I’ll let you know how CD Projekt
Red fixed that nasty cow-killing exploit. I’m Mark Brown, and this is Game Maker’s Toolkit. So first things first, what is an economy? Well, in games at least, it’s a term that
describes the flow of resources around a system. And resources covers just about anything
you can collect - coins, crafting materials, swords, experience points, ammo.... ARTHUR: "Money!" So everything from Stardew Valley to Elden Ring to DOOM Eternal to Pokemon has an economy. And
they share most of the same basic entities. Let’s start with this one: the tap.
Taps generates new resources into the economy. That could be enemies who
drop experience points when they die. A saw mill that harvests wood. A regenerating
health bar. Or rocks that spit out iron ore. Some taps generate resources automatically, on a timer
- others need to be mined manually, by the player. Now the thing about taps is that can be
used to incentivise player behaviour. If you want players to fight monsters, then
you can put loot drops on the enemies. If you want to push players to explore the world, then you might put unique crafting materials
in every biome. And if you want players to punch demons in the face, then shower them with
health points when they glory kill baddies. Also, just like a real tap… you can change the
flow of resources. This will affect how scarce, and valuable, a resource is: from rare
ammo drops in a survival horror game, to an abundance of munitions
in a fast-paced shooter. But, that can also affect the pace and balance
of the game - more on that in a bit. Oh, and, in extreme examples, a broken tap
can create economy-busting exploits. When we get resources from taps, we put
them in our next entity - the inventory. Which, could be an actual inventory
that you can rummage through. Or it could describe a simple counter
like a health bar or coin wallet. Whatever the case, you need to decide if it
has an upper limit or not. Giving players a maximum carry weight, or forcing them to
stash every gun in a tiny attache case, can create challenging decisions about
what items are most essential, right now. And a limit can also be used to stop
players amassing too much wealth - and it forces them to actually use
these resources and not just carry a thousand potions until the end of
the game because, you know, just in case. Now here’s the thing about resources. Some of them are inherently useful - like swords and guns.
But others, like experience points and money, don’t actually do anything on their own. They
need to be exchanged for something more useful. So say hello to our next entity: the converter.
Anything that lets us exchange one resource for another. Like spending
money on new gear in a shop. Or crafting a better weapon from raw materials.
Or cashing in experience points to level up. Now in some games, the cost of a conversion is
going to have an impact on the pace of the game. For example, if we know how much XP we need to
level up, and how many experience points drop when an enemy is killed, we’ll know - roughly
- how many enemies the player needs to slay before gaining new power. And so
that progression can be sped up, or slowed down - by changing the cost of
the conversion… or the output of the tap. Now, converters can be a great way to
encourage decision making in the player. Like, whenever you go to a shop you need to carefully
decide how to spend your limited pool of cash. But, it’s easy to mess this up. Look at Ghost of Tsushima: it has about
13 different crafting materials, and most are directly linked to a specific upgrade. Yew
wood for ranged weapons. Leather for armour. Iron for your sword. This means that you don’t have to
make a decision about how to use these materials, because upgrading one bit of gear often
doesn’t impact your ability to upgrade another. That’s very different to Metro: Exodus, which
only has two crafting materials: components and chemicals. And pretty much everything you
can make - from ammo to mask filters to health packs - requires both. So, because crafting one
thing temporarily locks you out from crafting another, it means you have to be smart and
intentional about everything you bash together. Having lots of currencies can be great for
encouraging exploration. Or making certain conversions much rarer than others. But if you
want to create difficult decisions for the player, have fewer currencies… that can be
spent on lots of different things. So what are we actually exchanging
these resources for? Well, typically, it’s something to make the player more powerful,
more efficient, or more resilient. Bigger swords and better armour, so that they’re ready to face
the challenges in the next part of the game. But what about if players can
return to the area they just came from, but now with better gear,
stronger stats, and more health? Well, for some games, that’s what makes
them fun. Idle games like Cookie Clicker, and roguelikes with permanent progression
make players repeat the same, or very similar, content - but each time, with more
power or efficiency than before. This creates a positive feedback loop - a system
where the output is fed into the input, and then reinforces the output more strongly. And it can
be very compelling - and dangerously addictive. But you know what else we might
call repeating the same content to slowly amass power? Grinding.
And that’s not always what we want. So, maybe you want to get rid of
this power-creeping feedback loop, or at least make it
less tempting or less tedious. I mean, you could do what CD Projeckt Red
did when it came to fixing that cow-killing exploit. In a patch, released a
few months after the game’s launch, there was a rather cryptic new addition to
the game: the bovine defence force initiative. And what did the BDFI do? Well, if you killed
six cows in White Orchard… the game would spawn a level 27 monster nearby, who would rush
in and, well, put a stop to your rampage. So, that’s certainly one way to fix it. But,
here’s three other smart ways to go about it. One method is to make that power creep more
interesting, by turning it into a puzzle. Take a look at Factorio: it has the exact loop I just
described. You start by digging up a small amount of coal and iron - and then convert those into
plates. You can then use those new resources to create more drills and furnaces, that will let
you repeat that same process more effectively. But as you go along - creating conveyer belts
and production lines and different energy sources - you realise that it’s not just a simple,
obvious loop of gaining power. Instead, it’s a complex problem-solving headache of automation
and optimisation. Games like Satisfactory and Stardew Valley are fun, because they challenge
players to figure out how to be more efficient. What’s the smartest conversion route for
a certain resource? How does the layout of your factory effect its efficiency? Where are
backlogs and stoppages happening, and how can you redesign to stamp them out? Can you keep
up with repair and maintenance? And how might a change in circumstances - like a sudden drop below
minus 100 degrees celsius - change your plans? Plus, while you can just
slowly amass wealth over time, you’re encouraged to optimise with
deadlines, rewards, and competing nations. Another way to get rid of grinding is
to implement a negative feedback loop. A system that works to balance itself to a
status quo. In. Elden Ring, if you graph out the number of runes needed to unlock the next
level, then you’ll see that it makes a sharp, upward curve where it costs more and more
experience points to jump to the next level. So while you only need to dispatch about 10 guards
in Limgrave to jump from level 9 to level 10, you’d need to kill hundreds of them to go
from level 49 to 50. By changing the cost of the conversion in lock step with your level,
Elden Ring makes killing the same simple enemies over and over again incredibly ineffective
- massively discouraging this tactic. And so players are pushed to explore further afield,
fight tougher monsters, and take bigger risks. The final way to deal with grind is to
slow it down, by implementing another economic entity. The drain. Drains are the opposite of taps
because they permanently remove resources from the economy. That includes breakable weapons. Losing
health or units. Paying taxes or feeding citizens. And when you shoot a gun, you’re draining
your ammo count with every bullet fired. So, just like the power-gaining loop from before, drains send players back to the tap - but
this time, without getting stronger. Because, they’re just replacing the stuff that was
lost. So, this slows the player’s power growth, because they have to spend time and
resources to merely patch up their losses. But that’s not the only reason drains exist. They can also force players to get on and act.
A hunger meter that’s constantly going down forces players to look for food. And
crops that spoil after a certain time will need to be accounted for in your
optimised schedule. Drains can also force you to mix up your strategies - Zelda’s
breakable weapons can be a bummer, but they do make you try out new swords, and encourage
you to explore the world and find replacements. Drains can also add risk. Back in Elden Ring,
your stash of experience points can be lost when you die - and, as we saw before,
you need to carry more and more of them on your person before you can level up.
So this adds a real sense of danger when exploring new areas - one which grows
and grows the more runes you’re holding. Or, look at Death Stranding. It’s tempting
to take a huge number of packages at once for a massive payout, but every extra
box on your back increases the risk of taking a tumble. And because boxes can
be destroyed - or drained - upon impact, you’re at risk of losing everything. It’s
all about weighing up the potential reward. It’s worth noting, though, that drains can also
be positive feedback loops - just for losing power, rather than gaining it. Consider how in Monopoly,
every time you lose money you become less and less able to compete with other players, sending you
in a painful downward spiral towards bankruptcy. I did a whole video on this conundrum,
in the context of losing units in XCOM, a few years back. I’ll put a link
to it in this video’s end screen. So, there’s one more type of economic
entity that’s not quite as common, but can lead to some really interesting gameplay.
It’s the trader. Traders act like other players: they have their own inventory and resources.
And will buy, sell, and trade stuff based on their own desires and rules. Think of the
other nations and city states in Civilization. So, previously, I lumped shops into
converters. And in a lot of games, that’s exactly how they work: you simply convert
money into items. Like a vending machine. But look at the merchants in The Witcher
3. Each one has their own stash of items and wallet of money - and they will buy
and sell items for a different price, based on what type of shop they run and where
they’re located. This means that enterprising players can buy items for cheap in one area
- and then sell them for a profit elsewhere. With traders, we can create complex puzzles
of trade routes and investments - and reward players for being canny with how resources may be
valued in different places, or at different times. Though, just like converters, traders can
potentially create a positive feedback loop of the player getting richer and richer
with every transaction - so you may need to implement a fix for this. That might involve
modelling supply and demand. In Moonlighter, a cute game about raiding dungeons and then
selling the loot in your shop - you can flood the market with an item and drive its price down.
You can’t just repeat the same sale forever. Or, you could add an element of risk to
the investment. In Animal Crossing you can buy turnips on a Sunday at a certain
cost. And then, every day that week, the Nook shop will buy those turnips
for a different price. If you’re lucky, you can turn a huge profit on
your investment. But if you’re unlucky, you’ll never see a good price before the
turnips drain out of your inventory next weekend. It’s basically a miniature stock market, and by adding a sense of risk and reward, we
not only go some way towards fixing the exploit, but we add extra decision making. How much am
I willing to risk? What’s the right reward? So this is our final economy. Resources are
created in taps. We store them in inventories. We can exchange them for something
more useful with converters - though sometimes they’ll be lost into
drains and need to be replaced. And some games may even include traders, who want
to buy and sell their own stock of resources. As resources flow through the system,
the way these entities are designed and balanced is going to change the
pace, challenge, and feel of the game. Of course, this graph is not going to describe
every single game. Simple titles may not have every single entity, or every route for resources
to flow. And it certainly doesn’t describe massively multiplayer games and those
with real-world money transactions. I think I’ll leave that to the in-house
economists and future finance ministers. Before I go, though… remember that story about
how CD Projekt Red fixed the cow exploit by spawning a massive monster into White
Orchard? Well, it was all well and good until higher levels players realised
that this monster could be killed and its head sold for a huge profit. And all you
needed to do to spawn one was kill a few cows. So the devs had to patch the game
again. Now, the monster only spawns once. Like I said, video game
economies can be pretty complicated. Hey, thanks for watching. This video was originally a lecture I
gave at Breda University of Applied Sciences in The Netherlands. When I was there, I ended up
giving four different lectures on various topics. And so if you’re a GMTK Patron on the video
tier, I’ve just released a recording of the first talk - which is about techniques I use to analyse
games. Thanks so much for supporting this channel.
