SOUNDTRACK · 2026-07-11

Soundtrack: FRACT OSC — solve the puzzle and the music grows back

Mogi Grumbles (Alex Taam)

Reviewed by Doremi · #soundtrack #music #fract-osc #ambient #synthesizer #generative #sound-design

Introduction - the first sound to light up in a powered-down world

When FRACT OSC begins, I am standing inside a vast hollow made of wireframe. It is first-person exploration in the lineage of Myst and Riven, but what has decayed here is not a ruin of stone - it is a stalled synthesizer itself. This world, built by Phosfiend Systems (Richard E. Flanagan and Quynh Nguyen, Henk Boom), is, as Komugi's review covered, constructed out of sound. The first thing to touch my ear is a soft-edged sustained pad and a low, steady pulse throbbing in the distance. The tempo is, roughly, around 70 - placed less to be counted than as a heartbeat to settle my stride.

The lead voices are soft synths and oscillators with a hardware-like texture, composed by Alex Taam - known as Mogi Grumbles. No showy melody plays yet. Thin-overtone sine-ish pads, and noise that slowly opens and closes its filter. That half-powered incompleteness, as if the world's switch is only partway on, is the first soundscape. I take a sip of black coffee and realize: this quiet exists so that I can break it later, myself.

A puzzle-native trait - you don't 'listen' to the track, you 'assemble' it

What decisively separates FRACT OSC from an ordinary soundtrack is that most of its music does not play in finished form from the outset. The puzzles here are the insides of giant sequencers and synths themselves; when I step on the switches in the right order and enter the right patterns, the machine comes back to life and adds a new layer of sound. Solve the bassline puzzle and the low end lights up; solve the arpeggio puzzle and the upper voices start turning. In other words, I am not appreciating a piece - through the data-entry labor called a puzzle, I am raising the music of that spot one tier at a time.

In a section I've finished, the generated sound simply keeps playing as ambience. And the 'Studio' unlocked from the midgame on - a room where you freely wire up the synths and effects you've gathered in-game - reveals the floor beneath this design. The puzzles were, in the end, a long tutorial for turning the player into a composer. It is consistent that the retry cue is never spiky: when I fail, the world does not scold me, it answers only with the silence of 'not yet lit.' Failure is treated not as a deduction but as the dark before the lamp comes on.

The hidden link with the experience - the decision to align everything to one key

Here is the verified piece I most want to hand to anyone who composes. In a PAX East interview, Taam said that, 'to keep things simple, he kept all of the pieces of music in the same key.' The game's music is, for the most part, in C pentatonic minor. This is not laziness but an almost inevitable choice as generative-music design. No matter what order the player solves the puzzles in, no matter which layer lights up first, if everything sounding sits inside the same scale it can never turn muddy. Freedom of exploration and order of harmony are reconciled by a single constraint.

A pentatonic scale carries no semitone clash between adjacent notes. So even accidental overlaps don't turn dissonant, and even when the player touches things improvisationally, a 'wrong note' is hard to produce. For FRACT OSC - where the world itself is an instrument and the player's trial and error is directly the performance - this is a safety net and, at the same time, the unified color of the world. Had the labyrinth been built atonally, exploration would have been a run of anxiety. By fixing a single key, Taam lowers the tension of exploration from the music's side - mechanics and harmony are tied together by one and the same decision.

The analogy with the puzzle - slow sustained tones keep pace with a groping tempo

I always have the habit of measuring music in BPM, but FRACT OSC's exploration has almost no clear beat. And that is right. What I am doing in this game is groping time - walking a dark hollow, staring at a machine, hesitating over where to step. If a 120 four-on-the-floor were pounding there, it would rush my hesitation and ruin it. So the base music is made of 'layers' rather than beats: pads that open slowly, an intermittent low pulse - time is not pushed forward, it only thickens.

And only at the instant of solving does rhythm rise. The arpeggio spins, the sequence locks in, and the fog of sound that had been drifting suddenly gains a skeleton. The curve of puzzle-solving thought - the long stall, then the single instant of understanding - is laid directly over the music's shift from 'sustain to pulse.' Give the stall no tempo; give tempo only to the achievement. That, as I see it, is the musical backbone of FRACT OSC.

Tracks worth hearing - from official sources

First, the launch trailer on developer Phosfiend Systems' official channel. In a short span you can grasp how Mogi Grumbles' sound melts into that wireframe world.

One more, from the same official channel: 'FRACT featuring Mogi Grumbles!' - a video where you can taste how the game's sound is built and how it rings, through the composer's own audio.

To sit down and hear the whole thing, go to Mogi Grumbles' own soundtrack on Bandcamp (a 2019 remaster exists). Freed from the game's layered structure, 17 tracks are lined up, reassembled into finished form.

In closing - the one thing I'd steal if I were composing

What I carry back to my own work is just one thing: 'For music meant to sound interactively, design it after first fixing a single key.' If the order is decided at will by the player or the system, and you still don't want it to muddy, push every layer into a scale where clashes rarely happen, like a pentatonic. The shortest move for reconciling freedom and order is right here. And there's a big production ease to it: you no longer have to worry about tonality each time you add another piece.

For a re-listen, late at night while sketching with no deadline is best. Inside the reassurance that nothing you add will turn dissonant, your fingers start assembling a puzzle on their own. If you want to lean into the safety net of C pentatonic minor, try listening alongside the sustained tones of COCOON - also a game where 'the world itself is an instrument' - and the loop-that-never-tires design of Manifold Garden. I'll pour myself one more coffee.