For most game designers, making a video game that is enjoyable for players is a big enough challenge.

Making a game that is enjoyable for players and spectators is a bigger challenge yet. Then there's making a game that is enjoyable for players and spectators and allows the spectators to interact with the players through the game. It's relatively uncharted territory. But it's what Climax Studios did in its zombie survivor game Dead Nation: Apocalypse Edition.

The standard edition of Dead Nation is a top down shoot 'em up in which players try to survive a zombie apocalypse. The Apocalypse Edition of the game for PlayStation 4 features a mode that not only broadcasts the game to Twitch, but also allows the stream's spectators to have a say in how the game plays out.

"The audience had to be able to break the balance of the game; they had to be able to be dicks..."

"I was really keen to get the audience involved, and I was looking at what was practical and what we could get into Dead Nation so it still feels like part of the game," said Climax Studios' senior technical designer Claire Blackshaw. "I had this idea of making the audience a zombie horde, and from there it was a natural evolution to getting the audience to decide your fate."

When spectators tune in to watch a player's Dead Nation stream, they're given voting powers. Periodically, all the viewers of a particular stream — whether they're watching on their PS4 or in a web browser — have the option to vote between a positive or negative effect that occurs in the game. These options range from helping the player by giving them ammo and changing the game's difficulty setting, to hindering them by spawning zombies and disabling the player's ability to sprint. By encouraging the input of spectators, the dynamics of the game change entirely. The difficulty of the game becomes unpredictable, and whether the player gets stuck in a sticky situation with unrelenting zombie hordes or whether they cruise through sections of the game picking up ammo is decided by the audience.

In turn, the spectators appear in the player's game as zombies, and the player can exact revenge on them.





While Climax Studios has been able to pull off the audience and player interaction, Blackshaw told Polygon that it was no small feat to get it to function both on a technical and a design level.

"It's actually a really huge challenge, and I think it's a whole new area of game design we need to start tackling," she said. "We started talking about it over the last year or so with eSports, and how to design a game for streaming in terms of making your game design play well when streaming to an audience, but once you actually involve the audience in some way, it gets a lot complicated."

The game's Broadcast+ mode was in development well before Twitch Plays Pokemon, so there were few precedents set. The development team had to consider the technical aspects of latency and ensure viewers on a stream didn't experience a delay between what they were seeing and what the player was doing. And because the game was in development before the launch of the PS4, the developers could only test the feature internally.

"I think that every game going forward needs to consider how well it performs on a shared stream..."

"We had to guess what the audience would be like and how mean they would be, and it was really a leap of faith in a lot of ways," Blackshaw said. "It was completely unproven and there was no way we could see how fun it would be until the game launched, other than doing these small internal tests.

"When you have eight people watching and voting, it's nothing compared to when you've got 200-500 people watching. So it was a leap of faith on our side."

From a design and balance standpoint, the feature had to be structured in such a way that the audience could "break" the game without making it unplayable.

"The audience had to be able to break the balance of the game; they had to be able to be dicks, because if you look at things like Reddit of general internet communities, people don't get enthused unless they can break the game."

A post-launch patch has since been released in response to how audiences have interacted with players.

Blackshaw doesn't believe such a feature is suited to every game, and it is not necessarily something that everyone wants to experience. The average user has a very different way of playing games compared to broadcasters who have subscribers, so the core of their experience is different. Even so, she believes it's something developers should think about.

"I think you can build an entire game based on the broadcast mode and interactivity, but for most games, it's not going to work, and for the games that want to do it, I think it's best done as an additional mode or as a supplement because interactivity for it to do anything meaningful, it has to be able to break the game or it has to be wired directly into the core game loop.

"I think that every game going forward needs to consider how well it performs on a shared stream," Blackshaw said. "I think that's something we should just be conscious of now."