How Chunk made a game based on sleep

How Chunk made a game based on sleep
Craig Chapple

By Craig Chapple

December 18th 2013 at 4:25PM

The Scottish developer discusses how games can be used for positive lifestyle change and the challenges of using sleep as an input in Zeds

Games aren't always simply about mindless destruction, and can often be used to gamify serious social, mental, physical or lifestyle issues.

Earlier this year interactive entertainment firm Chunk released Zeds on mobile, designed to be played around the player's sleeping routines. It does this by measuring the quality of sleep, and adapts the levels accordingly.

To find out more about the challenges of developing games for children and using a unique input such as sleep as a core element of the title, Develop spoke to Chunk owner Donnie Kerrigan.

Could you explain the concept behind Zeds and how it is played?

Quality of sleep is a problem for teenagers; too many energy drinks, too many late night chats, gaming sessions and too much brain stimulus before falling asleep. To raise awareness we created Zeds, a platform runner game for iPhone and iPod, where you have to get Zeds, little folk who live in your sleep, safely home through dangerous dream worlds. And it is actually your sleep - the game has a built in sleep monitor and each time you record your sleep the game delivers a brand new level based on it.


The aim of the game is to guide all your Zeds home safely


Why did you decide to develop a game revolved around sleep?
We created the game for Channel 4 Education. The first step of the brief was open, “what teen issue could we address with an app or game?”, but they actually answered the brief before we could! We were researching different topics when Channel 4 threw sleep into the ring and that was that.

Quality of sleep is an important subject for everyone really, but because of the constantly stimulating world we live in there are a lot of kids sleep-walking through some of the most important and formative days of their lives - so it’s a good choice.

How do you measure quality of sleep through a smartphone?
The truth is you can’t do it absolutely accurately. The sleep apps that are out there are saying “this could be what’s going on”. The experts we spoke to have purpose built equipment, like heart and brain monitors which aren’t available in the typical smartphone - yet!

Our goal was to raise awareness and give the big picture in an entertaining way, rather than create a scientifically accurate diagnosis, so a “this is what could be happening” result was enough to give teenagers the right level of understanding.

How did we do it? When people have a good sleep they go through 90 minute cycles, where they move from light to deep sleep and back again. By tracking their movement and noise during sleep we estimate when and how often people break out of that good cycle. Deep sleep is when people really recuperate and recharge; if we detect they might not be hitting deep sleep we tell them. And if that coincides with feeling tired it might encourage them to investigate it further.


Recording your sleep produces a graph of your sleep cycle and tells you what it might mean

What kind of development technology did you use to make the game?
When we chose a technology for Zeds we had a few things to think about. The sleep monitor needed direct access to hardware features such as the accelerometer and microphone and a fairly extensive interface, which at that time pointed to a native build; but we wanted to have the potential to port the game to Android at some point and there were elements of game that mixed 2D and 3D.

In the end we opted for a hybrid approach, using Unity for the game and native iOS for the sleep monitor and interface, allowing us to play each of the technologies to their strengths and making future porting more efficient.

What are the challenges of developing such a unique concept?
Having the idea is the first one. The second is the will to say “we’re going to do this!” even though you've never done it before and are starting from a position of zero knowledge. Luckily we enjoy those kind of challenges.

In terms of building the sleep monitor, it was really understanding sleep and what we could actually tell from the device - if anything! We worked with a number of sleep experts as part of the research phase and got a sense of what was possible and useful. Once we had that it was figuring out how to measure and report it. The rest was just the standard challenge of making a game!

How do you shape the game mechanics around the idea of sleep and how the player might be feeling when they play it?
The main connection to sleep comes from the levels and their design. They’re built from your sleep data, so reflect the sleep you’ve had. For example, when you’re in periods of light sleep the levels are a bit more fragile, with more leaping and quick play; if you manage to hit periods of deep sleep you’ll reach areas that contain Zs, which give your team leader a period of immunity - helpful when in lighter sleep periods. If you’re continually in light sleep it’s more difficult - but that’s how life is too!


Zs found in deep sleep give you temporary immunity


In terms of the feel, it’s tempting to think about the mythology of sleep and characters like Hypnos or the Oneiroi, and in the early days we did - but it felt too fantastical and wanted to create something more casual and accessible for everyone.

How do you ensure players come back to play it?
Every sleep produces a new level to play, so if you want new levels you’ll keep recording new sleep data - game design in your sleep! Also, points are based on the number of Zeds who make checkpoints and get back to bed safely; the more you play, the more Zeds you add to your team and the more the Zeds rank up - multiplying your score. The Zeds leading the team are most likely to die first, so the secret is in continually re-ordering your team and ranking them up cleverly.

And the more you play the more nice new bedclothes the Zeds get - who doesn’t want nice new bedclothes?


The higher your Zeds characters rank, the more points they can earn in levels


Do you think more developers could be making games that can have a positive impact on a player's lifestyle?
Yes, without a doubt - and not just games that impact the player’s lifestyle but games that impact on everyone. There are lots of people putting lots of effort into making virtual goods or maintaining virtual stuff for example. Can something be as fun and also contribute to self-improvement or greater good? What’s the digital equivalent of Innocent's little woolly hats?

The secret is in making sure it's entertaining and not relying on being worthy - even with the best will in the world most people will only learn or contribute so far if they’re not getting more back than a sense of 'doing good'.

Is there anything you'd like to add?
We’re hoping to create something that does what I’ve just described, so watch this space!