Subway Surfers: Lessons from the world's most downloaded game

In the almost 10 years since it first launched, Subway Surfers hasn't just enjoyed truly phenomenal success. It has equally set the standard for what mobile games as live, maintained entities can be.

That's true creatively, commercially, technically -- and even in terms of the positive cultural impact the endless runner hopes to leave with its players. That means there's a great deal other studios and publishers can learn from a look at the story behind Subway Surfers' many achievements.

Frequent and thoughtful updates sit at the heart of Subway Surfers' wild popularity, with the recently deployed North Pole 2021 holiday content marking the 137th edition of the Subway Surfers World Tour series. That's an update schedule with a typical turnaround cycle of between three and four weeks. While that may sound a little terrifying to some developers, SYBO has much in place to make sure both the frequency and quality needed are absolutely achievable.

But before we get into why that matters, it's worth considering just how successful SYBO and co-developer Kiloo's game has been. As of August 2020, Subway Surfers had been downloaded over three billion times in total -- a considerable percentage of the planet's 7.8 billion total residents. And at the last count, it stood as the most downloaded mobile game of the past decade.

"We have been adapting and evolving Subway Surfers while keeping the nostalgia feel that makes this game one-of-a kind."

Mathias Gredal Nørvig, SYBO

Importantly, from its original conception, the game -- which uses the Unity engine -- was designed with a frequent update process in mind. That is how it has continued to attract and beguile players through almost a decade of service. Though, of course, updates are not the only reason the game has banked lifetime revenues that are estimated to be in the billions of dollars.

"Our success can be attributed to many factors: simplistic yet super appealing game play, engaging and familiar characters, combined with high quality, state-of-the-art animation, graphics and moves that amplify the play experience," said SYBO Games CEO Mathias Gredal Nørvig, before touching on the matter of those updates. "We have been adapting and evolving Subway Surfers while keeping the nostalgia feel that makes this game one-of-a kind."

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A tour de force
The concept of the World Tour was introduced into the game in 2013, and has since become emulated by countless titles from studios and publishers of every size, to the point it is one of the most familiar ways to continue to engage and retain new and existing players across the mobile gaming landscape. The World Tour concept as realized by SYBO essentially transplants the game and its core principles and mechanics to different global settings with each new update, providing new themes founded in real cultures, enabling the team to constantly refresh the context around Subway Surfers' central offering.

Interestingly, however, a focus on what not to change is perhaps the defining concept of such a successful update strategy, all the while understanding just how much can be changed or added to.

"Keeping to our roots has always been paramount," confirms game director Christian Balazs. "The basis of Subway Surfers has remained pretty much the same: run along subway tracks, collect coins and power-ups, and dodge obstacles. To keep things fresh and provide new experiences within the framework itself, we insert surprise elements like mixing up power-ups and new characters. But we like to amp it up as well. For instance, in our Vancouver update in November, players could choose to run in two different cities -- Vancouver or New York."

And that process, Balazs says, isn't too far removed from the gameplay itself.

"It's like Jake surfing on top of a subway car... it's a fine balancing act. Our fans continue to play because they love the jolt of excitement as they escape oncoming trains, amass coins, and high scores. Integrating new play elements, improved aesthetics, and such in a deliberate way -- as opposed to massive changes all at once -- keeps gamers coming back."

Here it is also worth considering that the World Tour updates also serve as a vehicle for evolving Subway Surfers more generally. While the game design core may remain largely unchanged since its debut in 2012, SYBO has had to make sure it's most iconic title continues to feel contemporary as the broader medium undergoes continual evolution and improvement. Which brings us to a key point: frequently updating and modernizing a game over many years requires a meticulous blend of creative practice, production management and technological pipelines that bring both productivity and efficiency. Getting all of that right lets a title like Subway Surfers keep pace with player expectations around the likes of visual quality while also maintaining an effective and retaining seasonal content strategy.

"We're always striving to provide the highest quality product, content and experience," states Balazs. "At each level -- from concept, to creation, beta testing and all the steps in between and through launch -- it's imperative that we excel. Thankfully, Unity allows our designers and programmers stellar tools to use when implementing design, menu and sound."

That means that from the perspective of game modernization, engine choice has played a significant part in enabling the SYBO team to constantly refine the likes of Subway Surfers memory usage, growing complexity in graphics used and the emergence of ever more advance content delivery networks (CDNs); while also keeping the World Tour updates on track as an engaging means to keep content feeling fresh. Picking Unity gave SYBO a singular place to manage all those things, ensuring quality while keeping every member of the team involved in an efficient update process.

Though, of course, the people that make up those teams are the most important factor in making Subway Surfers the decade-long sensation it is.

Inclusive culture. Inclusive technology
"At SYBO we strive to have the strongest and most experienced game teams," Gredal Nørvig enthuses. "We have an inclusive and relatively flat structure and we expect every artist to be able to contribute with everything game related; this includes implementing assets into Unity.

This means that all artists on Subway Surfers, including concept artists, are expected to do work inside Unity on a regular basis. We do use source control so that we can always roll back should anything be messed up majorly, but in general we aim to educate people to be able to work safely inside Unity. Other than that we make tools that can be run in Unity and or external content creation software to minimize repetitive tasks and human errors."

SYBO's choice of game engine, then, has empowered every kind of artist to be part of both the technical process and the broader effort of making Subway Surfers thrive. The value of bringing those artists closer to the game development process is fundamental to making the World Tour strategy and release cadence not just impactful, but also sustainable. Empowering artists to work directly in Unity has the direct effect of making iteration loops faster while maintaining quality and creative excellence, all with a view to hitting those all important three-to-four-week content drop deadlines.

But how does Subway Surfers -- which was the first ever to see one billion downloads on Android alone -- address the challenge of deploying to the myriad device models and OS variants that it currently supports?

"We have a frequent cadence of release updates that our players are used to and look forward to," explains Balazs. "Our goal is to deliver fun and reliable updates. Unity allows us to seamlessly manage built-in and CDN content between releases, while keeping build size in check, which are crucial for a reliable release schedule. Moving most of our assets to addressables allow us to use memory wisely, so that even low end devices can keep experiencing new content and features. We want to ensure that all players have a good experience when running the game, and addressables support us in achieving this objective."

Games with purpose
Away from talk of engines and pipelines and the power of addressables, there is something else that has helped Subway Surfers phenomenal growth, and it's something that a great deal more players will care about than the way you structure your production pipelines.

Here, we're talking about authenticity. And for SYBO, it is authenticity of values; values that go way deeper than simply staking a flag in a certain worldview.

"Our values are how we live and work every day," Gredal Nørvig confirms, as conversation turns to the fact that the World Tour is also a way to celebrate and share cultural diversity. "We initiate campaigns like Play 2 Plant [which has seen us plant] 200,000 trees because we have strived for a more sustainable Earth for over a decade."

That same spirit, it turns out, is very much part of the effort behind the World Tour.

"We introduce diverse characters because it reflects the world in which we live," Gredal Nørvig continues. "Every month, 100 million-plus people play Subway Surfers, allowing us to inspire, educate, and empower our fans to be kind, proud, aware while having fun."

The tremendous success of the game from a commercial and creative standpoint is certainly something any game company can learn from, but what might be all the more encouraging is that Subway Surfers is ultimately a game about exploring different cultures. The fact that well over a third of the planet are so interested in such a game is an encouraging thought when the world can feel so divided. And that is one of the most exciting potential of games. As well as being pieces of entertainment that make a lot of money for their teams while bringing a great deal of pleasure to players, they can be tools that breed empathy and open-mindedness.

That's something clearly on the mind of both Gredal Nørvig and Balazs, as they conclude with some advice for game teams hoping to learn from SYBO's experience.

"Surround yourself with individuals that support your vision, who can be cheerleaders and critics. Keep at it, be willing to try, expect some failures and learn from them. Do not negotiate on insisting everyone live the company's values. We are performance driven, yes, and we are also playful and creative. We are still in the building stages of our company, and thus, we learn from each other every single day. So bringing an optimistic attitude to the game, literally, is key."