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Clash Royale's card balancing guru leans less on metrics, more on design intuition

"We tend to put stuff in that we tested to see how it feels. Then test it again, and so forth. That’s one of the core benefits. It’s not like I take something I designed, like a unit, then hand it over." - Stefan Engblom of Supercell

Kris Graft, Contributor

March 21, 2017

9 Min Read

There’s no doubt that metrics and data are important when balancing a live multiplayer game. But when it comes to balancing the top-grossing title on mobile, a lot of the direction comes from plain ol’ game designer gut feeling.

“It really boils down to intuition, and looking at [player] videos -- and playing the game yourself. You’re going to learn,” Clash Royale designer Stefan Engblom said in an interview at Game Developers Conference earlier this month, where he gave the highly-informative talk, “Quest for the healthy metagame: Balancing cards in Clash Royale.”
“We don’t really have a process. It’s like random chaos,” he laughed. “That’s pretty much how it sometimes feels.”
Supercell’s hugely popular head-to-head card-based strategy game rakes in tens of millions of dollars in revenue per month, driving the studio’s reported $10.2 billion valuation. Chinese internet giant Tencent owns a majority stake in the Finnish studio, which also develops Clash of Clans.

Behind those staggering financials is a Clash Royale team made up of just 16 people, Engblom said in his GDC talk. Calling the game’s continued development “random chaos” is a bit self-deprecating. The important process for balancing the game’s card system emphasizes agility, with little bureaucracy and short idea-to-release cycles. The process may be loose, but the design goals are clear.

"I roll around in my chair and say, 'Hey! This would be a cool thing to do! What do you think about it?'"

“I would say that it is [guideline-driven],” Engblom told us of the game’s development process. “It is a very iterative, very pragmatic approach. We tend to just put stuff in the game that we tested to see how it feels. Then we test it again, and so forth.”
“That’s one of the core benefits,” he said of being on a small team. “It’s not like I take something I created or designed, like a unit, then hand it over to the designer. [It’s not] as if someone would give something to me to take to a lead programmer [who would] take it to a programmer. … We don’t have that. I roll around in my chair and say, ‘Hey! This would be a cool thing to do! What do you think about it?’”
“Then I go and grab a coffee and when I’m back he’s already implemented it into the game,” he said. “Then we test it and see how it goes.”

The guidelines

Engblom said in his GDC session that even though he is the only one with the title of “designer,” the members of the Clash Royale team “are all kind of designers.” He specifically works on card balancing, economy, and system design, but the team collaborates on all decisions.

Engblom explained a baseline rule that Clash Royale’s design follows: for every level gained, players gain 10 percent damage and 10 percent hit points. “This means all interactions remain the same at all equivalence levels,” said Engblom. But perhaps more importantly, “This helps keep me sane,” he said.

When dealing with card design and balancing, Engblom said there are three guidelines he and his team follow: fun, variety, and freshness. All changes, whether it’s nerfing a unit or adding a new one, need to serve at least one of these categories.

A huge part of following those guidelines involve maintaining and improving Clash Royale’s metagame. For Engblom, he defines metagame as “cards combinations, and strategies that the community at large have found most effective.”

The metagame isn’t something a developer necessarily can create, he said -- that’s up to the players. It’s like a toymaker making a toy with the intention for it to be played with in one specific way, but when in the hands of a child, they find a different way to enjoy it.

Even though game designers can’t necessarly decide exactly what the metagame will be, Engblom said designers can influence its path. “Balancing is the tool to steer [the metagame] in the direction we want,” he said.

The best that a game designer can do is to avoid a broken metagame, and understand that a perfect metagame is unrealistic. Landing somewhere in between a healthy and unhealthy metagame is where balancing comes into play.

“You want to have a healthy metagame,” he said. “That’s the ultimate goal. The quest for the healthy metagame.”

Principles for balancing

So how does a designer support a healthy metagame? There are a few specific principles the Clash Royale team at Supercell follow:

Make everything FEEL overpowered. The emphasis here is on the word “feel.” This can be achieved in a few ways, such as through a game’s art style. But from a balancing perspective, in order to achieve this feeling, each card needs to have its “moment” -- a clear purpose. “There needs to be enough situations where the card can bring huge positive value,” Engblom said.

Everything needs a counter. Then counters to the counters. That’s where the metagame evolves. This doesn’t only contribute to the game’s fun, variety, and freshness, but it also takes some pressure off of the designers. When you have multiple counters, and counters to counters, you are that many steps away from totally breaking your metagame. The counters serve as a “safety net” for card balancing, Engblom said.

This isn’t necessarily an excuse for bad balancing, but poor metagame tweaks are inevitable, he said, and in those cases it’s better to have a fixable, unhealthy metagame than a totally broken one.

"There needs to be enough situations where the card can bring huge positive value."

Make new cards meaningful. New cards need to serve a purpose, he said. Don’t just release a new unit so you have something you can charge players for. 

“When you press ‘battle’ [in Clash Royale], you exit that realm [of monetization],” he said in an interview, calling the game “pay-to-progress” rather than “pay-to-win.” In Clash Royale, players pay to unlock cards and level them up more quickly than playing for free, but there are no consumable boosts one can buy and then deploy for an advantage when going head-to-head with other players.

Instead of creating new cards for the sole purpose of monetization, try to use new cards to fill gameplay gaps, he said. And don’t just reskin existing cards or units.

Keep old cards relevant. The introduction of new cards doesn’t mean that old ones should become useless, Engblom stressed, and to “stay true to the soul of the card.” But when rebalancing old cards, make sure to:

  • avoid complete reworks of those cards (only make small changes to the basic stats)

  • when reworking, make sure the changes are easy for the player to predict

  • make sure that the card or unit essentially plays like it did prior to the change

Keep on rebalancing. Supercell rebalances about once a month. “There’s no exact science to this cadence,” Engblom said. “That’s just when the metagame felt like it was getting a bit stale.”

“At the beginning the reactions were a bit negative,” he said, “...but over time, as we kept doing them...players began to appreciate them and look forward to them as well, so it was a good thing.”

That one-month cycle keeps balance on point and fresh, but it also gives the metagame time to evolve, said Engblom.

He added that “buffs are nicer than nerfs,” as “nerfs hit cards that most use.” On the other hand, “buffs hit cards that only a few use.”

While all of this tweaking is going on, communication with your community is important -- regularly manage expectations via clear release notes and other community initiatives, such as Clash Royale’s in-app “Radio Royale” show.

What to balance (and what not to balance)

Decisions on what to balance and how are based on player feedback, data analysis, but most of all, the intuition of Clash Royale developers.

Engblom said player feedback is “an invaluable tool.” Often, devs need to read between the lines of player feedback -- their complaints about one component of the game might have an actual cause elsewhere in the game.
“Players can and will teach you about your game,” said Engblom. For Clash Royale, the game’s top players are the trendsetters for the rest of the player base, creating decks and coming up with strategies that will be copied by the game’s playerbase. By following the highest-profile Clash Royale players, he can get an idea of the direction the rest of the community will follow.

"It really does just boil down to play, play, play, play, play."

“Especially with the hardcore players, when the balance changes come, they’re like, ‘Ok, what will happen, how will the meta shift?’” he told us. “More casual players will sometimes be a bit upset…but I think in general it’s good for the game.”

Data feeds into player feedback, and can be used to verify or better understand player input. For Clash Royale, “it’s mostly looking at use rates and win rates,” when it comes to balancing -- that is, what players use and what they use to win. Use rates tell Engblom and his team the state of the metagame and also indicate what cards might be overpowered. Win rates, he said, can show sleeper cards.

Determining a good use rate for card ultimately down to intuition and “knowing your game,” he said. Designers ought to figure out why a card is popular and determine if it is overpowered, and if it is good for the metagame.

Balancing cards also involves weighing the use rates of what Engblom calls “bread and butter” cards versus “spicy cards.” Bread and butter cards have high use rates and are commonly used for base strategies while spicy cards are ones that aren’t as commonly used but can be highly effective when used by skilled players. Both types have their own role in Clash Royale.

Understand advanced concepts

Developers on games that require constant balancing need to stay on top of advanced strategies that players use, said Engblom. You cannot rely on intuition to make decisions when you are un- or under-informed.

Know strategies, deck cycles, common opening moves, and so on. “It really does just boil down to play, play, play, play, play,” Engblom told us. “Just play the game, iterate, play, tweak.”

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