Bunny Hop

The meadow, and how a run ends

The track is 600×150 units, with the ground line 127 down from the top — wide and shallow on purpose. Vertically the only question is whether you are above an obstacle or under it, so there is nothing to gain from depth. The width is how much warning you get: even at the run’s top speed, the far edge of the meadow is still 0.77 seconds ahead of you.

The rabbit does not move along the track. It stays 24 units in from the left edge and the meadow slides past it, and every obstacle’s position is read from the distance you have run rather than accumulated obstacle by obstacle — so nothing has drifted out of place 3 minutes into a run.

• The run ends the first time you touch an obstacle. There are no lives and no seconds of invulnerability — one touch is the whole of it.
• There is nothing to finish. The meadow is endless, and what a run leaves behind is a score.
• Before you start there is a ready state: the world stands still until your first input, so opening the game can never cost you a run.
• Your first hop is also what starts the run, so the track itself never asks you to find a separate start control.

A rabbit that has been hit loses its eye. That is the whole of the end-of-run effect — no explosion, no debris and no screen shake — and it says the run is over without a word that would need translating.

Controls

There is one input in this game, and it is the hop. There is no crouch and no second input, because every shape on the track is answered either by hopping or by doing nothing at all.

• Tap anywhere in the play area to hop. The track is a shallow band on a tall phone, so your thumb never has to go looking for the strip itself.
• Or use the Hop button along the bottom, drawn as a single ↑ across the width of the screen. In a game decided by how long it takes to find the control, the target should be enormous — and it carries a name, so assistive technology can reach it too.
• In a browser, Space, the up arrow and W hop as well. While the Hop button has focus it handles its own keys, so one press never hops twice.
• You can only hop from the ground. There is no second hop in mid-air: with one, every gap on the track would become survivable and the shapes would stop asking anything.

The hop is two numbers and no more: it leaves the ground at 580 units per second against a gravity of 2100, which makes it 80 high and 0.55 seconds long. How far a hop carries, and how wide a gap has to be to be fair, both fall out of those — so there is no third dial to turn.

Seven shapes, and the one that punishes a reflex

Seven shapes make up the meadow and all of them ask the same single question: hop, or don’t. What changes between them is how strict the timing is — a single bush forgives a late hop, a row of three does not — and, in one case, whether the shape is a hazard at all.

• The low bird flies at the rabbit’s own height, so it is hopped exactly like a bush. A bird is not automatically something you can ignore.
• The high bird is the one shape that punishes a reflex. It passes clear over a rabbit that stays on the ground, and can only ever catch one that is already in the air. The answer to it is to do nothing.
• A bird’s hit box is its body, not its picture. The drawing is 46×40 with a wing that is up in one frame and down in the next, and neither the wings nor the beak can hit you — dying to something you visibly cleared is worse than a bird that looks bigger than it is.
• The bushes and hedges are drawn exactly to their boxes, so with them what you see is what you have to clear.

The rabbit’s own hit box is its drawn 40×42 shape pulled in 4 on every side, so a pixel of visible overlap is never counted as a death. Boxes and drawings are declared in two different places, so a test compares them mechanically — that is how a row of bushes drawn 44 units short of its box, killing runners on apparently empty grass, was caught.

It gets faster, not busier

Exactly one thing rises as a run goes on, and it is speed. The track starts at 340 units per second and gains 3.6 for every second you stay alive, up to 780, which it reaches after about 2 minutes and then holds. Density is not part of the curve: the gaps stay in the same band of seconds at every speed, so the meadow gets quicker rather than more crowded.

• Gaps are set in seconds of running, not in pixels — 0.72–1.6 seconds of clear track, measured from the back of one obstacle to the front of the next. A gap that is fair at 340 and impossible at 780 is not a gap; it is a countdown to an unavoidable hit.
• The shortest gap, 0.72 seconds, is longer than the 0.55 seconds a hop spends in the air. An obstacle can never enter while you are still committed to clearing the one in front of you.
• A high bird is given at least 1.1 seconds of room behind it. It is harmless while it is overhead; the only way it could be unfair is if the next obstacle forced you to hop while it was still there.
• The two score thresholds in the table are the only points at which the contents of the track change. After 400 it is the same seven shapes for the rest of the run, just quicker.
• The meadow is generated from a seed, so the same seed replays the same track, and a golden test keeps it that way across app updates.

Speed follows the seconds you have survived rather than the points you have scored, so two runs are moving at exactly the same speed at the same moment, however differently they have scored.

The score, and the help you get

The score is the distance you ran and holds nothing else: 40 units of track is 1 point. There are no multipliers, no combo counters and no bonus for a near miss.

It is drawn on the track itself rather than in the app’s status row — zero-padded to 5 digits in the top right, with your best score to its left, marked HI, once you have one. Those digits are the same rectangles the rabbit is made of, so they need no translation and no font to load. The score is still published as a labelled value for screen readers, which cannot read a canvas.

• Every 100 points the score blinks once. It is a landmark, not a reward — no bonus, no multiplier and no fanfare follows it. With Reduced Motion on it does not blink, and neither do the clouds, the pebbles, the stride or the wingbeats; the track itself keeps moving, because the track is the game.
• There is no Undo. Real-time reflexes are the content here, and stepping one back would empty the game out.
• There is no Hint. Nothing is hidden — everything you have to answer is already on screen, coming towards you.
• The help is an instant retry, unlimited and free. The result screen shows your score, the obstacles you cleared and your best, and puts Hop again first among its buttons; the same retry sits in the top right of the game screen. There is no confirmation step and no waiting.
• There is no continue to watch an ad for and no extra life to buy. There is no free revive either — "survive a little longer" is the shape of a thing that gets sold later, and this game does not carry that shape.
• No run is saved. Restoring a real-time meadow would only drop a hedge in front of you the moment it loaded, so leaving the game ends the run — while your statistics and your best score are always kept.

Statistics are four numbers: games played, best score, obstacles cleared and total play time. There is one best score for the whole game, since there is no difficulty and no level to split it by, and play time counts only while the meadow is moving — not while you are waiting to start, and not on the result screen. No streak is recorded, and there is no online ranking: a leaderboard is a server someone has to keep paying for.

Tips

• Read a bird’s height before you move. The low one flies at the rabbit’s own height and is hopped like a bush; the high one clears a running rabbit completely, so hopping is the only way it can ever hit you.
• Hop for the obstacle in front of you, not out of nerves. While you are clearing one, the next cannot reach you — the shortest gap is 0.72 seconds and a hop lasts 0.55 — but a hop you did not need is exactly how a high bird catches you.
• The wide shapes are the ones that punish sloppy timing. A single bush is 18 across and forgives a late hop; the three-bush row is 106 and does not. Learn them by silhouette, so you are answering the shape rather than reacting to its leading edge.
• Expect the track to change twice. At score 150 the clusters start appearing, and at 400 the birds arrive — the point where the question stops being "when do I hop" and becomes "do I hop at all".
• After about 2 minutes the speed stops rising for good. A run that survives the ramp is not going to get any harder; from there it is only how long you can keep reading the track.
• Trust the hit boxes rather than the outlines. The rabbit’s box is pulled in 4 on every side and a bird’s box is its body alone, so a wing sweeping through your silhouette is not a hit. Flinching at one is.

Questions people ask