GROUNDRUSH

Step off a 240-metre granite lip at first light. Freefall two seconds while the suit pressurises. Then fly 2.9 kilometres of canyon — and get paid for every metre you don't leave between yourself and the rock.

Points come from one place: the ground. Score flows only while rock or timber is inside 20 metres, scaled by closeness × airspeed, under a heat multiplier that climbs to ×8 while you keep it lit and bleeds out in under three seconds of flying safe. And the whole number is provisional. Hit the mountain — or pull too low for the canopy to breathe — and the run's score is forfeited on the spot. It banks the moment your feet touch down under a full parachute. The leaderboard only ever sees what you landed.

How to fly

• ↑ / ↓ (or W/S) — flare and dive. Dive to buy speed; flare to spend it as float. Hold the flare too long and the suit stalls, and the only way out is back down.
• ← / → (or A/D) — bank. The turn follows the lift; a full roll reversal takes over a second, so fly ahead of the canyon, not at it.
• SHIFT — tuck. Smaller wing: more speed, worse glide. A burst tool, never a freebie.
• SPACE — deploy. The canopy takes ~2.75 seconds to breathe, which costs 29 metres from cruise and nearly 60 out of a dive. Choose the moment; then steer in and hold SPACE to flare the landing.
• Mouse: hold one button anywhere and drag. Touch: left half is the stick, DEPLOY on the right. Keyboard alone flies everything.

The line

THE EXIT and its arête, THE FACE, THE SPINE, THE NARROWS — a 26-metre slot with a badge living inside it — then THE PINES (about 1,220 of them) down to THE MEADOW, a windsock and a gravel bullseye. The same mountain every run. It falls away at 1.84:1 and your best glide is 2.90:1, so staying close to the ground isn't a stunt — it's the only way down the hill that pays.

A first landing banks maybe 600–2,500. A line that threads the slot and skims the timber runs 3,000–7,000. clean-sweep starts at 9,000. Five badges, one hidden.

How it was made

Conceived and written by Claude Fable 5 in one scheduled run; the simulation was built and playtest-tuned by Claude Opus 5 in the same session. The flight model is real: a fixed 1/120 s timestep, a lift/drag polar whose 2.90:1 best glide was measured rather than asserted, a stall that bites past 16° angle of attack, and a parachute whose minimum survivable pull height emerges from its inflation drag ramp instead of a hard-coded altitude check. Reference lines were flown by a tree-aware autopilot in a headless browser before shipping — the tightest machine-flown centreline banks 8,510, which is why clean-sweep sits at 9,000: it requires the walls.