Developer interview: Unknown Number: A First Person Talker

One of this year’s most innovative new gameplay concepts came from developer Godolphin Games when they released Unknown Number on Steam – an interactive thriller where your voice is your controller. Dubbed a “first person talker”, it was such a novel concept that we reached out to the developers to find out more. Here’s what they had to say:

How did you come up with the core idea for Unknown Number?

Unknown Number came from the realisation that voice-control is bizarrely absent from the world of games. This is partly because innovation in gameplay formats is pretty rare, but also because no-one had yet managed to demonstrate that voice control could be a fun way to play a game.

So that was the challenge: find the fun in Voice!

Telephone calls were a pretty obvious extension of that mission – since they provide a natural-feeling context for players to start talking. We started off exploring *real* telephone calls – with players calling real numbers using their real phones, to access a series of gamified hotlines. This obviously came with a whole host of problems – not least the lack of imagery, and phone bills (should have predicted this one!). But, after lots of experimentation, the final shape of Unknown Number started to come together: a voice-controlled thriller for PC, that simulated the experience of phone calls, supplemented by a whole load of visual stimuli.

Who’s on the team behind the game?

The core team is pretty tiny – just a game designer (me) and a programmer. But the game has had major contributions from other people – most importantly for art, audio, and storytelling. Because these were the areas of expertise we needed to make this new format really work.


For art, it was a question of finding ways to bring life to the tight constraints of the mobile interface – which involved everything from working with an experimental typographer, to a shoot with a fashion photographer to create a set of ‘board-member’ portraits for our fictional in-game oil corporation.

In terms of audio, 50% of what’s going on in the game is communicated through sound alone. And so it was vital to make the sound design as vivid and personality-filled as possible. Working with music producer EASYFUN, We created the audio for Unknown Number over six weeks – locked away in a makeshift studio filled with hunks of metal, smashed glass, weird old machinery, and anything else that might help recreate the sounds of a creepy abandoned oilrig.

For story, we wanted the whole game to feel like a classic 90s thriller movie – so we worked with a writer/director who had experience writing these kinds of narratives for film and TV.

What are some of the specific challenges you had to face while designing and programming Unknown Number?

With such limited precedent for voice-controlled games, our design process was a fundamentally experimental one. We began with a series of rough hypotheses, most of which had to be radically revised during development.


To name a few…

-The game started life as an audio-only game, told through REAL-LIFE phone calls. This was inspired by the audio-only games on Amazon Alexa. But we quickly realised that visuals provided an essential crutch for PC gamers to even start engaging with voice-control.

-We began with the ambition to let players ‘say anything’, taking inspiration from the field of Natural Language Processing. But we got a far better response when we explicitly told players ‘what to say’ in each moment, through a series of tightly-constrained interaction windows.

-Using speech-to-text models as guidance, we originally designed puzzles based solely on the language uttered by players. But we discovered players often had more fun when we used the microphone in less conventional ways – whether that was whispering, shouting, singing, and even (at alpha) blowing.

So yeah, we made every mistake in the book… but there wasn’t even a ‘book’ to start with! Unknown Number changes that by providing a rare working example how voice-control CAN work in games. Our hope is that other developers can use it as a model to carry the torch forward. Long live the ‘First Person Talker’!

Between dialects and accents, how do you make sure that voice recognition works smoothly in a game like this?

The game builds on existing voice-recognition technology, so we weren’t starting from scratch with recognising accents etc. But we did do a load of additional work to ensure that our dictionary of ‘recognised words’ included a whole bunch of phonetic variations – to accommodate a diversity of pronunciation.


We’d imagine that a game like Unknown Number could be incredibly immersive when played with a touch interface. Is this something you’d consider doing in the future?

There were plans for a mobile version of Unknown Number during the early stages of development. But we eventually opted to discontinue that version since the small screen was unable to accommodate all the FMV elements – that we feel are crucial to the experience.

For our next project, we have a couple of things on the boil – both using natural language in their core gameplay loop.

The first is a very ambitious project that would use natural language in a much freer, more dynamic way than Unknown Number – and in a totally new gameplay context. The second is a tighter, smaller, arcade-style game – that might well end up on mobile. Whichever we end up progressing, the ambition is very much to carry the torch of Unknown Number forward – but in a way that takes the learnings from that game in a totally new and unexpected direction.

In the meantime, we are also in conversations with other developers in the Voice space, doing our best to foster the next generation of First Person Talkers.

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