Soundtrack: INSIDE — Telling a story about the inside of a head, through a head

Introduction — propulsion without a pulse

A boy runs right, and right again. Someone is chasing him. In an ordinary action game this is where a sprinting cue would rise; INSIDE plays none. All you hear are footsteps and brushing grass, a distant dog, and a low sustained tone welling up from beneath the ground. Out of habit I tried to clock the BPM, but the needle wouldn't move. What's here isn't a beat but a pressure — the directional weight of air pushing you rightward. In this 2.5D puzzle-platformer Playdead made after LIMBO (Komugi's review), the audio was handled by two people: Martin Stig Andersen and SØS Gunver Ryberg.

The palette is mostly analog synth, cold electronics that recall 1980s horror films. Yet all of it sounds somehow damp, muffled, as if it were ringing inside your own head. That instinct is very nearly correct: the sound of this game reaches our ears after passing through a real human skull.

Ringing a skull — behind the making

In interviews Andersen describes the starting point plainly: he was fascinated by how the sound of your own voice sounds very different in your own head. He acquired an old human skull, played the synth pieces he had made back through it, and re-recorded them as the bone and teeth resonated — a kind of bone-conduction filter. Sound that passes through bone turns brittle at the edges and takes on a hollow ring. The vibrations were reportedly strong enough that the skull's teeth fell out one by one. Some of the audio, it's said, was even recorded through a microphone placed inside a man's stomach.

This processing extends the thinking Andersen showed on LIMBO: for each project, fix not a 'musical style' but a single 'sound quality', and let it be the glue for the whole world. For INSIDE that glue was 'sound heard inside a head'. So even the electronics never ring mechanical; they feel like the interior of a living body. Its GDC Best Audio win, and its audio nominations at The Game Awards and the BAFTAs, are in my view a victory for that one consistent decision about texture.

The hidden link to play — into someone else's head

Why does 'passing sound through a skull' fit this game so tightly? The mechanic at INSIDE's core is mind control: through a helmet-like device you hijack other bodies and walk them at will to solve puzzles. Throughout, the player is inside someone. There is not a single line of dialogue; the world speaks through its environment alone. Over that, sound that has travelled through the inside of another person's skull is laid — theme and material aligned about as literally as they can be.

The music mostly sinks into silence, and only at the moment something happens does a synth bleed in like a ghost. The chase, the water, that huge mass of bodies near the end. When sound rises in those scenes, only then do we realize 'so that was music'. Silence as the floor, sound only for events. This subtraction carries the eeriness of a story about controlling and being controlled — not as explanation, but as sensation.

The puzzle analogy — quiet while you think, bone rings only when you move

Most of INSIDE's puzzles are made of observation and run-ups. Where to set the crate, how to change the water level, in what order to move the body you've hijacked — the player stops, reads the environment, measures the timing. If music draped a melody over that thinking time, it would create a beat that collides with the tempo of your own calculation. So here it must be silence, or a sustained tone with no outline. Sound whose needle won't move, keeping company with thought whose needle won't move.

Then the solution sets off — you're chased, you leap, you make it or you don't — and in that instant the bone-passed sound suddenly thickens. Density syncs only with where the puzzle's tension peaks. And because this is a die-and-learn game, you replay the same scene again and again. A melody-built track would tire the ear by the third try; a texture-built sustained tone survives the retry. INSIDE takes the 'retry-proof music' learned on LIMBO and deepens it with the damp of bone — that's how I heard it.

Tracks worth hearing

INSIDE's soundtrack was released on 7 July 2016, the same day as the game. It's less a conventional, cleanly-divided 'album' than a continuum edited to follow the experience. The audio lives officially on developer Playdead's SoundCloud and on composer SØS Gunver Ryberg's Bandcamp. Listen from the top, all the way through, first. More than any track boundaries, the flow of silence and bone-damp filling up in turns is what feels like this work's 'track'.

・Playdead official SoundCloud: INSIDE (full) ↗

・SØS Gunver Ryberg official Bandcamp: INSIDE ↗

Plenty of unauthorized full-length uploads sit on YouTube, but since I can find no clear official YouTube source for this work, I point only to the official SoundCloud and Bandcamp here. Sound that has passed through bone is best heard on good gear, in a quiet room.

Closing — what I'd steal if I were writing it

What I take home is the single move of binding timbre itself to the world's theme. INSIDE rang a story about the inside of a head through a physical resonator — a skull. You can copy this without owning a skull: a metal can, an empty bottle, a wooden box, or convolution with a recorded object's impulse response (IR) will give electronics the feel of having passed through some body. For each project, fix one texture as the glue, and build it before the melody — that's where I'd steal.

The other is the courage to subtract. Set silence as the baseline and sound only for events, and a single smear of synth becomes the cue that something is happening. Next time you boot INSIDE, sit in a quiet room and give yourself to that rightward pressure. You'll confirm, through bone, how eloquent sound without melody can be. Heard alongside LIMBO, the technique Andersen honed across two games — speaking by not playing — comes into fuller relief.