There's something terrifying, in a very primal sense, about the way total strangers invade your world in Dark Souls.
The first time it happened to me, I almost quit the game. The hair on the back of my neck prickled with fear that another human being was in the game -- and somewhere, somehow, they were doing their best to take me out.
Over time I came to relish the thrill of being hunted, and it seems I'm not alone. Popularized by From Software’s Souls games, the concept of players invading each other’s games has inspired developers around the industry to come up with interesting new ways of blurring the lines between single-player and multiplayer experiences.
From big-budget 2014 debuts like Watch Dogs to more contemporary projects like Dying Light, developers seem excited to pick up what From Software is laying down and play around with ways to inject similar levels of tension and uncertainty into their own work.
But that entails answering a very critical question: what is it about the way Souls games implement player invasions that make them so compelling, and how do you make it work in other contexts?
“Everything comes from the indirect communication,” says From Software’s Atsuo Yoshimura. “That’s what makes the Dark Souls franchise so unique.“
Yoshimura served as global producer on the recently-released Dark Souls II: Scholar of the First Sin, an updated version of Dark Souls II with (among other things) a more robust multiplayer system. Speaking with Gamasutra at a recent event, Yoshimura explained his belief that player invasions are popular because they add an element of mystery to the game.
“Invasions, and even co-op partners...players are not sure who is actually playing, controlling that,” said Yoshimura. “Because there is no guarantee that they actually help or not, that's what makes the gameplay so unique.”
But alongside that unique appeal comes a host of new design challenges, and every developer has to figure out their own way of injecting a similar air of mystery into their work.
First, there’s the purely technical challenge of making a game in which players can seamlessly transition back and forth between each other’s worlds. When Ubisoft was working out how to make the player invasion system in its open-world action game Watch Dogs feasible, senior producer Dominic Guay remembers the trickiest part being the peer-to-peer synchronization.
“Our engineering team had to ensure that our sandbox could be synchronized between peers...a big challenge considering the amount of simulated elements in our game,” said Guay. “Moreover, we could not significantly compromise on the simulation’s quality since this needed to remain ‘seamless.’”
But Guay says these technical hurdles were cake compared to the more complex design issues that arise when you start allowing players to invade each other’s games.
For example, how much do you tell each player about what’s happening when an invasion occurs? The line between mysterious and frustrating can be thin: players of Demon’s Souls and its spiritual successors can invade each other’s games simply by using an in-game item, but they transform into a glowing crimson spectre and a big ol’ warning flashes on the invaded player’s screen.
"It creates a feeling of paranoia. That was a nice addition."
But in Watch Dogs, players take on missions to enter another (willing) player’s game and either hack them directly or tail them without being spotted. The invaded player doesn’t always know when they’ve invaded -- they’ll typically only be notified if they try to start a mission or their invader fouls up -- and working out what information to give each player when proved to be tricky business for Ubisoft.
“When we first started testing, some players did not believe another player was in the game world, even when we told them verbally it had happened,” says Guay.
Ubisoft ultimately felt it was important to take a more direct role in guiding the player’s expectations than From Software did with its Souls games; thus, Watch Dogs explains its hacking and tailing multiplayer modes up front (and allows players to opt out of participating) while maintaining an air of mystery by not always informing players when they’ve been invaded.
“It creates a feeling of paranoia,” says Guay. “That was a nice addition to our aesthetics for the overall game experience.”
Guay says Ubisoft still has a lot to learn about how to best implement player invasion mechanics (“we just scratched the surface of what is possible and we have learned a lot from our experience”) and that it adds an interesting dimension of difficulty to the design of open-world games.
Rather than starting with a level playing field, it creates an undulating landscape, with steep hills and valleys"
He’s not alone, either; Dying Light director Adrian Ciszewski says Techland built a player invasion mode called “Be The Zombie” into its open-world zombie survival game in order to keep players on their toes.
“Players have to work harder in order to put themselves in the mindset of their opponents and anticipate their moves,” he tells me. “Rather than starting with a level playing field, it creates an undulating landscape, with steep hills and valleys, which players have to learn to use to their advantage.”
The “undulating landscape” of Dying Light is a multiplayer co-op mode that players can drop in and out of at will, either joining the protagonist’s side or triggering “Be The Zombie” mode and becoming a super-powered undead antagonist.
Like Watch Dogs (and unlike the Souls games) it affords players more direct control over when they can be invaded, since it only occurs during multiplayer co-op sessions. Ciszewski says the team quickly stopped worrying too much about invasions becoming annoying (“After all, who wouldn’t want a zombie to come alive with human-level intelligence?”) but that it struggled to solve more mundane design problems.
Take, for example, resource management: Dying Light is a survival-focused game where things like flashlight batteries are precious, but they’re also critical to the invasion mode because human players can use them to power a UV flashlight that drains the stamina of the human-controlled super-zombie.
So is it best to disable that mechanic during an invasion, or just let things ride a la Dark Souls?
For Techland, the former answer was the right one. “We didn’t want the player to have to deal with resource management when fighting the Hunter,” says Ciszewski. “So early on we decided to suspend most resource drain,” including those precious batteries.
He says the studio had a much tougher time working out how to make player invasions feasible without ruining the player’s progression through the story and its various quests. Imagine, he says, what would happen if an invader stomped in and tried to whack the player while they were in the middle of a cutscene.
“It’s easy to ring-fence the bigger set pieces, but what do you do about less important dialogue? Do we block invasion while an NPC is delivering its line, or do we allow both to proceed?” says Ciszewski. “The NPC AI in Dying Light was never programmed to deal with the Hunter so we didn’t want them to come into contact anyway, to avoid awkward situations, particularly in safe zones.”
In the end, says Ciszewski, the Dying Light team chose to disable shops, encounters and story-progressing AI for the duration of a player invasion and the invader was prevented from entering safe zones by flooding them with UV light.
“This created a knock-on problem of people camping out in [UV-flooded safe zones],” says Ciszewski. “The answer to that was a limited time in which you can hide there, or you lose.”
In hindsight, both Ciszewski and Guay appreciate the way that player invasion systems add a fresh, unpredictable element to their games.
“By adding more complexity we’re making the game more challenging and, by extension, more rewarding,” says Ciszewksi. Guay remains adamant that such multiplayer modes “open up new ways of playing together with other players” in an obtuse, mysterious way that’s “exciting to both players and developers,” echoing sentiments expressed by Bandai Namco’s Brian Hong.
“My personal feeling is that [Souls creative lead Hidetaka Miyazaki’s] intent was to make sure that Dark Souls...it forced you to interact with people that you didn't know,” Hong opined, speaking to Gamasutra alongside Yoshimura at the afore-mentioned Dark Souls II event.
“It was very deliberate to make sure that the bloodstains, and the messages, and the way you communicated was supposed to be very opaque. So that people come to their own conclusions.”