Fair by construction
Every level is generated from a fixed seed and then played by a solver using the game’s own physics with a bigger hitbox than yours. Layouts it cannot clear are thrown away, so there are no blind jumps or impossible gaps.
About Us
About gravityrun.app
We make Gravity Run: a free, one-button gravity flip runner for the browser, with 18 levels that are each proven beatable before you play them.
The whole game
Which way is down?
The runner handles speed. You handle gravity. Every design decision serves that one choice.
- Levels
- 18
- Stars to find
- 54
- Button
- 1
What we make
A gravity runner that lives in the browser
Gravity Run is a single-player arcade game. Your runner rolls through a tunnel at a fixed speed, and every tap flips gravity so it falls to the ceiling or back to the floor. Spike strips, pits, saw blades, bolts, and needles end the run on contact. Reach the finish gate to unlock the next level; collect three stars on the way for a perfect clear.
There is nothing to download and no account to make. The game is the website — a small static page with the game drawn on a canvas — so it loads quickly on phones and older laptops alike, and your progress is saved in local browser storage.
This page speaks only for gravityrun.app. The controls, hazards, and level list in our how-to-play guide and FAQ describe this exact build.
Origins
Where gravity runners come from
Gravity Run sits at the meeting point of two ideas: the one-button auto-runner and the gravity flip.
- 01
One-button runners
Auto-runners strip a platformer down to timing: the character moves on its own and the player only decides when to act. Canabalt (2009) made the format famous with a single jump button, and it suited phones and browser tabs perfectly — easy to start, hard to master.
- 02
Flipping gravity
Around 2010 a run of games replaced the jump with a gravity flip. VVVVVV made reversing gravity the core of a puzzle-platformer, and Gravity Guy put the flip into a chase runner. Flipping changes the question from “how high?” to “which side?”, which is what makes the genre feel different.
- 03
Classroom classic
Browser versions called Gravity Run — most famously on kids’ game portals such as ABCya — brought the idea to a younger audience with short tunnels, stars to collect, and levels that unlock in order. Many players first met the genre on a school computer.
- 04
This build
gravityrun.app is an independent, from-scratch take on that formula for modern browsers. It is not affiliated with ABCya or any other portal. It keeps the loved parts — one button, 18 levels, three stars each — and adds saws, bolts, needles, instant restarts, and levels that are proven beatable.
Principles
What every level is built around
Instant to start, instant to retry
The tunnel is running behind the menu before you press anything. A crash restarts the level in about half a second with no reload, no lives counter, and no game-over screen to dismiss.
Honest controls
Physics runs at a fixed 120 steps per second regardless of your screen, presses made a moment before landing are buffered, and there is a tiny grace window after rolling off an edge — small allowances that make the game feel responsive without playing itself.
Yours to keep
Unlocked levels, stars, best times, and attempts live in your browser’s local storage. There is no login, so nothing is held behind one — and nothing leaves your device.
How it works
How a level is proven beatable
Because the runner always moves at the same speed, its position is fixed by time. The only decision is when to flip — and a flip can only start from the floor or ceiling. That means every moment the runner is on a surface can be described by just two things: the time, and which surface it is on.
The solver walks through every one of those moments and tries both choices — keep rolling, or flip — using the same physics code as the live game, but with the runner inflated so that a passing solution leaves real room for human timing. If no route reaches the finish gate, the layout is discarded and the next seed is tried.
Stars are placed along one of the routes it finds, so all three can always be collected in a single run. The attract-mode runner you see behind the menu is that route being replayed.
A readable tunnel
Hazards are always red or orange, the runner is always lime, and stars are always gold. Pits have red edges so a missing tile reads as danger at a glance, even at top speed on a small screen.
Warnings before surprises
Bolts are fired from off-screen, so a flashing arrow marks their lane before they appear. Saws follow a fixed, smooth sweep you can learn by watching one cycle.
A steady difficulty curve
Each block of levels introduces one new hazard at a comfortable speed before mixing it with the others. Speed climbs from 6.5 to 10 tiles per second across the 18 levels, and the space between hazards shrinks as you go.
Accessibility
Built to be playable by more people
The game needs only one input, which can be a tap, a mouse click, or any of several keys — useful for switch and one-handed play. Every on-screen control has a text label for screen readers and a visible focus ring, interface text meets WCAG AA contrast, and hazards differ from safe objects by shape as well as colour.
Sound is optional and remembered; the game pauses itself when the tab is hidden. There are no flashing full-screen effects. If something gets in your way, tell us.
Contact
Found a tough level or a bug?
Feedback on difficulty, a bug report, an accessibility issue, or a simple hello — we read every message.
Email usLooking for something else? Start here.