Play Sisyphus Unbound: The Stones That Freed Persephone — a free 3D ball-rolling puzzle in your browser
Sisyphus Unbound: The Stones That Freed Persephone is a free browser-based 3D ball-rolling physics puzzle set in the Greek underworld. You steer a single bronze stone down thirty hand-carved chapters of the pit: ice shelves that carry you too fast to steer, tar pits that grip and stop you dead, spring pads, crumbling flagstones, floor plates that raise portcullises, moving ferry plates, and a trap gallery of sliders, spinners, swinging hammers, armed bombs and gale corridors. Reach the well at the bottom of each chapter and another of the six seals holding Persephone breaks.
How to play
- Drag anywhere to steer. The stone accelerates away from your finger or cursor — the whole screen is a joystick and the stick's origin is wherever you touched down. A short drag is a nudge; a long drag asks for everything the ground will give. On desktop you can simply move the mouse without holding anything; the arrow keys and WASD work too.
- Respect the stone's momentum. There is no brake and no jump. The stone keeps the speed it has until friction takes it, and different floors take it at wildly different rates. Most chapters are lost in the two seconds after a turn, not during it.
- Learn the eight floor types. Basalt is neutral. Ice has almost no grip, so it preserves whatever you arrived with. Tar grips hard and stops the stone dead. Spring pads launch it over gaps. Crumbling flagstones fall away a moment after contact. Floor plates open portcullises. Ferry plates slide and carry the stone along. The well is the exit.
- Wait for the traps instead of racing them. Sliders sweep, spinners turn, hammers swing on an arm, and bombs arm the instant the stone touches them. They run on fixed cycles and none of them can be out-sprinted, so standing still and watching one full cycle is not wasted time — it is the move.
- Light the cold fires. A blue flame on the floor is a checkpoint. Light it and a fall returns the stone there instead of to the top of the chapter.
- Collect the embers. Embers sit off the safe road, usually one nudge away from somewhere you would rather not go. Three stars means reaching the well, losing no stones, collecting every ember, and beating par.
Controls
| Input | Action |
|---|---|
| Touch & drag (phone, tablet) | Steer — the stone accelerates away from where you touched down |
| Move the mouse (desktop) | Steer — the stone accelerates away from the cursor |
| Click & drag (desktop) | Steer from the point you pressed, useful for long committed pushes |
| ↑ ↓ ← → or WASD | Steer on the eight points of the compass |
| R | Restart the chapter |
| Esc or P | Pause — which freezes the traps as well as the stone |
The floor, exactly
| Surface | What the stone does |
|---|---|
| Basalt (grey) | Neutral grip. The reference surface everything else is measured against. |
| Ice (pale blue) | Almost no friction, so the stone keeps nearly all of the speed it arrived with. Ice is a delivery system and a hazard at the same time. |
| Tar (black pool) | Heavy friction. Arrives fast, leaves slow — a brake you can aim at, and a trap if you need to cross it. |
| Spring pad | Launches the stone upward on contact, clearing gaps and traps a roll cannot cross. |
| Crumbling flagstone | Sags the instant the stone touches it and falls away a moment later. One crossing per flagstone. |
| Floor plate (bronze) | Opens every portcullis ahead when the stone rolls over it. A shortcut, never the only route — every chapter is passable with every gate shut. |
| Ferry plate (sliding) | Slides along its axis and carries whichever stone is standing on it, which is the only way across some crossings. |
| Well (shaft of light) | The exit. The stone is pulled in and the chapter is over. |
| Cold fire (blue flame) | A checkpoint. Falls return the stone here rather than to the top. |
The traps, exactly
| Trap | Behaviour | How to survive it |
|---|---|---|
| Slider | Sweeps back and forth across a lane on a fixed period, and shoves the stone sideways on contact | Cross on the far half of its sweep, or cross on the beat when it is travelling away |
| Spinner | Rotates a bar around a hub; contact throws the stone tangentially | Pass when the bar is parallel to your direction of travel |
| Swinging hammer | Swings a head on a long arm through an arc, knocking the stone back down the corridor | Wait out one full arc; the safe window is when the head is climbing, not falling |
| Armed bomb | Arms on contact, then detonates once, shoving the stone radially and shaking the level | Touch it deliberately early, or never touch it. There is no third option. |
| Gale corridor | A rectangular region of the pit that pushes the stone sideways while it is inside | Enter it already angled into the wind — the wind is a constant force, not a nudge |
| Portcullis | Solid until a floor plate is pressed, then sinks into the ground | They are never required; the pit is always passable with all of them down |
The four acts
| Act | Chapters | What it teaches |
|---|---|---|
| I · The Ashen Foothills | 1–8 | Ash to the ankles and the first sky-wells: how the stone carries speed, and why ice and tar are two different kinds of danger |
| II · The Bronze Terraces | 9–16 | Hammered bronze and locks that were never meant to turn — portcullis plates, the first spinners, and the first checkpoints worth lighting |
| III · The Winds of Tartarus | 17–24 | The pit breathes and the breath is a wall: gale corridors, ferry crossings, hammers, and bombs on the only road down |
| IV · The Gates of Hades | 25–30 | Six seals, one goddess, no more favours — every mechanic at once on eleven-wide chapters |
Campaign versus the endless descent
| Campaign | Endless descent | |
|---|---|---|
| Structure | Thirty hand-carved chapters in four acts, each with a measured par time | Generated chapters that get deeper and nastier until the pit keeps the stone |
| Difficulty | Seven to eleven squares wide, up to eight traps, two winds, one to three embers | Starts around chapter six and climbs: more traps, more wind, more floor you cannot trust |
| Fairness | Every chapter was proved winnable by a reference rider before it was allowed to ship | Every descent is generated, proved winnable, and priced for par before you are shown it |
| What you chase | Stars and best times, one row per chapter | A single depth number, kept on your device |
Why par is a number you can trust
Most physics games fabricate their target times. This one measures them. Every chapter was handed to a reference rider — the same deterministic auto-pilot that the build script and the shipped game both use, so the thing that proves a level and the thing that plays it can never drift apart — and it was run at eight different trap phases, because on this pit the traps are on cycles and where they happen to be when you arrive is the single biggest factor in how long a chapter takes.
Par is then the slower of two numbers: the fastest run plus a third, or the median run plus a tenth. The first keeps par honest on a chapter whose traps always line up the same way. The second keeps it honest on a chapter where arriving at the wrong moment costs fifteen seconds — chapter 26, for instance, takes anywhere from nine to thirty-four seconds depending purely on when you show up. Taking the slower of the two is what stops par from being a time that one lucky rider hit once, and makes it a time a competent player actually reaches. Nothing under seven seconds is ever advertised, because no route in the game is that short.
Strategy that actually works
- Stop steering before the turn, not during it. The stone decelerates slowly and turns slowly. The two seconds after a corner are where chapters are lost, and releasing the stick early is the whole fix.
- Use tar as a brake, not as an obstacle. A tar pool at the bottom of a drop is a gift; the same pool in the middle of a crossing is the reason you fell.
- Ice is transport. Get onto ice pointed the right way and you cross half the chapter without spending anything. Get onto ice pointed the wrong way and you find out how much of the pit has no railing.
- Light every cold fire you pass, even out of the way. A checkpoint costs three seconds and saves a whole attempt.
- Do not treat the gale as a nudge. Wind here is a constant acceleration. If you fight it head-on you lose the whole width of the corridor; if you enter already angled into it you cross in a straight line.
- Bank the embers on an easy chapter. Three stars needs every ember, and on the chapter where you finally beat par you will want them already collected.
- Watch the trap for a full cycle before you move. Every trap in the pit is periodic and none of them change their period. One cycle of standing still buys you the whole chapter.
Technical notes
The whole game is one self-contained page: no third-party scripts, no trackers, and no network calls after load. There is no 3D engine underneath it either — the camera, the perspective projection, the depth sorting and every piece of geometry are written by hand and drawn onto a plain two-dimensional canvas, which is why the same scene scales from a 320-pixel phone to a desktop monitor without a single downloaded asset. Every sound is synthesised with the Web Audio API, including the continuous stone-on-stone rolling bed that changes pitch with the stone's speed.
The simulation runs on a fixed 1/120-second timestep, and there is no Math.random() anywhere in the rules, the physics or the generator. That means a run is a pure function of the chapter, the trap phase and your input stream — so the reference rider's winning line is not an approximation of what a player faces, it is exactly what a player faces. It is also why pausing freezes the traps as well as the stone: if the traps kept moving while the clock stopped, pause would be a free re-roll of every window in the level and par would stop meaning anything. Progress is stored locally under sisyphusunbound.save.v1; nothing is uploaded, because there is no server.
The chapter table ships as thirty pre-baked, pre-proved entries, and the tooling that produced it ships with the game: tools/bake.js carves every chapter from its own seed, runs the rider at eight trap phases, refuses any seed that does not clear the bar, and writes the resulting par times into js/levels.js; tools/verify.js then re-checks the shipped table from scratch, including a breadth-first proof that every well is reachable from its start both with every portcullis open and with every portcullis treated as solid rock. Re-running the baker produces the same seeds, the same routes and the same par times, which is the only reason the numbers on this page are worth quoting.
Sisyphus Unbound: The Stones That Freed Persephone — frequently asked questions
What is Sisyphus Unbound: The Stones That Freed Persephone?
It is a free browser 3D ball-rolling puzzle built on Greek myth. Every chapter is a stretch of the underworld you steer a bronze stone down: a start pad at the top, a well at the bottom, and ice shelves, tar pits, spring pads, crumbling flagstones, portcullises, moving ferry plates and trap galleries in between. Thirty hand-carved chapters across four acts, plus an endless descent that goes deeper until the pit finally keeps the stone.
How do you control the stone?
Drag anywhere on the screen — the stone accelerates away from your finger, so a short drag is a nudge and a long one is full speed. On a desktop you can also just move the mouse: the stone accelerates away from the cursor. The arrow keys and W A S D work as well. There is no jump button and no brake: the stone only ever goes where the floor and the slope let it, which is why the chapters are about reading the ground ahead rather than about reflexes.
Why does the stone only stop falling when it reaches the well at the bottom?
Because the well is the seal. Each chapter ends at a shaft of light coming up from below, and the stone has to be delivered into it. Everything between the start pad and the well is the actual puzzle: ice carries you far too fast to steer, tar grips the stone and stops it dead, spring pads throw it over gaps, crumbling flagstones fall away a moment after the stone touches them, and the trap gallery has to be crossed while it is in the right part of its cycle.
What happens when the stone falls off the edge?
You get the stone back at the last checkpoint you lit, or at the top of the chapter if you have not lit one. Falling costs a stone, and you begin each chapter with three. Lose all three and the chapter restarts — but falling also costs you the clean-run star, because one of the three stars requires reaching the well with no fallbacks at all.
What does the par time on each chapter mean?
It is a measured time, not an invented one. Every chapter was played by a reference rider at eight different trap phases, and par is the slower of two numbers: the fastest run plus a third, or the median run plus a tenth. The first keeps par honest on a chapter whose traps always line up the same way; the second keeps it honest on a chapter where arriving at the wrong moment costs fifteen seconds. Par is never a time nobody can reach. Reaching the well inside par, with no fallbacks and every ember collected, is the three-star run.
Does it work on a phone, and does it need a download?
There is no download, no account and no install: it is one HTML5 page that runs in the browser on desktop, tablet and phone, including a 320-pixel screen. On a phone the whole screen is a joystick — touch anywhere and drag. On a desktop the cursor steers. Progress, stars and best times are kept in your own browser.