Falling Sand Game FAQ

The falling sand game is a pixel-physics sandbox. The screen is a grid of cells, and every frame the whole grid is simulated: powders such as sand fall and pile up, liquids such as water and lava flow, gases such as fire and smoke rise, and materials react when they touch. You paint materials with a brush and watch the result. There is no score and no objective — the simulation is the point.

Yes. fallingsandgame.app is completely free and runs entirely in your browser. There is nothing to buy, download, or install, and there are no interruptive video ads, premium tiers, or paywalls. The simulation is already running when the page loads.

No. The game is the web page — a 100% browser-based build with no app-store download and no sign-up. Your material, brush size, and sound preference are stored locally in your browser, so there is no login.

The genre traces to Japanese web toys of the mid-2000s — most famously "Hell of Sand" (2005) — which let visitors drop sand, water, oil, and fire on a small Java or Flash canvas. Desktop projects like The Powder Toy expanded the idea into a full physics playground, and modern browser builds such as Sandspiel brought it back to a single click with no plugin.

Pick a material from the palette, then press and drag on the canvas to paint it. Sand falls, water spreads, fire rises and spreads. Use the brush-size control for a finer or wider stroke, press Space to pause or resume the simulation, and press Clear (or C) to wipe the canvas and start again.

No. This is a sandbox toy, not a puzzle or an arcade game. Nothing is scored and there is no way to lose. Some players build elaborate machines, others just make a mess with lava — both are playing it correctly. The site does keep small local counters (particles placed, materials tried) for fun, but they do not gate anything.

Space pauses and resumes the simulation. C clears the canvas. M mutes and unmutes sound. The [ and ] keys shrink and grow the brush. Number keys and material initials jump straight to a material (1 sand, 2 water, 3 stone, and so on), and E selects the eraser.

Yes. Press the pause button in the HUD or the Space key to freeze every cell in place. Painting still works while paused, which is the easiest way to lay out a precise build before letting physics take over.

The brush is a filled circle whose radius you set from the HUD or with the [ and ] keys, from a single cell up to a wide pour. Gases and lava paint sparsely so a click puffs a cloud rather than dropping a solid disc.

Wall, sand, water, stone, wood, plant, fire, smoke, steam, oil, lava, acid, salt, and gas, plus an eraser. Powders (sand, salt, stone) fall and pile; liquids (water, oil, acid, lava) flow and layer by density; gases (fire, smoke, steam, gas) rise and disperse; solids (wall, wood, plant) hold position, and wood and plant can burn.

Lava turns to stone and boils water into steam on contact; fire spreads along wood, plant, oil, and gas and is put out by water; acid dissolves sand, stone, wood, plant, and salt but not wall; salt dissolves in water; plant grows into any water it touches; steam condenses back into water as it cools; and a gas cloud flashes to fire the moment a flame reaches it.

Each material has a density. Sand, salt, and stone are denser than every liquid, so a grain that lands on a pool keeps falling until it hits something solid. Among the liquids, oil is lighter than water and rises to the top, while lava is the heaviest and sits at the bottom.

It is a cellular automaton. The grid is scanned each tick: powders and liquids are checked from the bottom up and try to move down or diagonally, gases are checked from the top down and try to rise, and a final pass handles stationary reactions like plant growth and acid corrosion. The whole thing runs at a fixed 60 simulation steps per second regardless of your display.

Yes. Boil water into steam with fire or lava under a wall ceiling. The steam rises, cools against the wall, condenses back into water droplets, and falls — a closed loop that will keep raining as long as the heat source lasts.

Yes. The canvas and the full material palette fit on one portrait screen, and painting works with touch and drag. Dealing with a smaller grid on a phone also keeps the frame rate high. Clearing and pausing are one tap.

The scene itself is not saved — closing the tab clears it. What persists is your settings (last material, brush size, sound) and a few lifetime counters, all in local browser storage on that device. A different browser or cleared site data starts fresh.

Frame rate falls when a very large fraction of the grid is active at once (a full screen of flowing water and fire, for example). Clear part of the canvas, use wall to contain a reaction, or pause and rebuild. The HUD shows a live FPS reading.

Any current browser with JavaScript and Canvas: Chrome, Edge, Firefox, and Safari on desktop, plus their mobile versions. If the canvas does not respond, update the browser, allow scripts for this site, and reload.

Open the stats panel from the HUD and use Reset, then confirm with the second tap. That clears the lifetime counters — particles placed, materials tried, sessions — on this browser. It does not affect the current scene and cannot be undone.