Steeplejack
A ladder of chimneys and spires, climbed at night by lantern light. A machine can prove a level beatable with frame-perfect play, which proves nothing about you, so these towers carry a harder certificate: a surveyor climbs each one the way a person does, rung to rung with its feet planted between moves, and then the tremor test shakes its line, sliding every jump press, release, and mid-air steer by whole frames, hundreds of times per rest. A tower only ships if no input needs better than the plaque's timing window and the shaken line still summits almost every time. Falls cost time, never progress, and the honest clock never stops: your whole climb is a code any browser can re-simulate and verify.
TypeScript · human-certified towers · verifiable run codes
every tower ships with a proof a human can climb it · your run is a replayable code · play full screen ↗
How to play
- arrows or wasd move, space jumps; on a phone hold it upright: left thumb steers, right thumb jumps
- the stride: land at a full run and hop again straight away to keep your speed boosted in the air; chain hops to fly
- hold toward a wall to slide, jump off it to kick away: flues are climbed on wall kicks
- checkpoint lamps on the balconies hold your progress: a fall costs the climb back to the lamp, never the tower
- ferries swing on rails and jackdaws patrol on fixed beats: everything moves on one shared clock, so time your catch
- red pennants are side bets hung off the route: touching one puts it on your belt, but only a lamp or the summit banks it, and a fall drops it
- the amber ghost is the surveyor's certified line; the red ghost is the stunt line that sets the gold bar: race either
- r restarts the climb, esc returns to the title
- the daily climb is the same tower for everyone; your result and your run code are shareable
Changelog
- 2026-07-22·The fun update, after Jonathan summited all ten and shrugged. Three answers to one verdict. The stride: the game's one piece of movement tech, Celeste-dash philosophy, one strong trick instead of five weak ones. Land at a full run, hop again inside four frames, and the air keeps your hurry, 3.6 pixels a frame against the usual 2.9; chain the hops and whole rungs go by underfoot. It is strictly additive, so every certificate still means what it said. Pennants: red side bets hung in genuinely nasty places, over shard pots, past a jackdaw's beat, off a ferry's far swing. Touching one is not keeping it: a lamp or the summit banks it, a fall drops it, Meat Boy rules, and every pennant ships with a machine proof it can be taken. Medals mean something now: the stunt surveyor, a pure-speed search that strides and clips shamelessly, sets the gold bar on every tower, and its line ships as a run you can race as a ghost; beating the certified line is silver, exactly what it used to cost to gold. The certificate also grew a dial: the shake magnitude is now part of the proof, which opens the door to ±1-frame expert remixes of the benched full-strength pieces; none certified tonight, so none shipped, and the door stays open.
- 2026-07-22·The tower gets moving parts, and the difficulty Jonathan asked for. Ferries: planks that trolley side to side on rails, all sharing one 180-frame clock, so the climb becomes WHEN as well as where. Jackdaws: the birds that nest in real chimneys, patrolling rungs and flight corridors on fixed beats; land in the gap or land in the beak. Shards arrive by tower two now, the first ferry at four, the first jackdaw at six, and the chimney gauntlets crown the ladder. Medals hang off the certificates: gold means you beat the surveyor's own certified line, and the ghost race now shows a live delta at every lamp. All ten towers re-certified: motion is a pure function of the frame counter, so the tremor test finally gets to bite on timing against something that moves, and every plaque still promises at least a 33 millisecond window on every input.
- 2026-07-21·The running bug, actually dead this time. The first fix trusted the browser to report every released touch, and phones do not always keep that promise. Touch input now rebuilds its held-state from each event's own complete list of live touches, so a release the browser never reported dies at the very next tap, and a ten second silence drops any hold as a last resort. There is a new test seam that deliberately loses a release and watches the ghost die.
- 2026-07-21·The tower learned to stand up straight. A climb is a vertical thing, so on an upright phone the game now plays portrait: a tall 360 by 640 frame with the whole height given to the tower, a slim top bar, and the controls down in thumb country, left thumb steering, right thumb jumping. Landscape and desktop keep the wide frame with its side panels. The full-screen page follows whichever way you hold the phone, no rotate request needed, and every screen letterboxes cleanly.
- 2026-07-21·The phantom walk is dead: a thumb that slid off the screen mid-hold could leave the climber marching on their own, because the release never reached the canvas. Touches are now captured for their whole life, releases are caught at the window, and every held input drops the moment the page loses focus.
- 2026-07-21·Full screen on your phone: the tower now lives at /play/steeplejack with no site chrome. Install it to your home screen for the app feel (landscape-locked on Android, chrome-less everywhere), use the fullscreen button where the browser allows one, and upright phones get a polite request to turn sideways. Your towers, bests, and daily results stay saved in the browser either way.
- 2026-07-21·The lamps mean it now. The first checkpoint build only caught deaths, so a slip that tumbled you to the street just left you on the street, which is not what a lamp is for. The rule is now the honest one: fall more than four rows below your lit lamp and it counts as a fall, back to the lamp, clock still running. Certified lines never descend more than two rows below a rest, so every proof keeps a two-row margin from the rule, and all ten towers re-certified under it.
- 2026-07-20·The playtest verdict was fair: too easy, too samey. So the towers went back to school with Celeste, Mario, and Super Meat Boy. Checkpoint lamps now glow on rest balconies every couple of sections, Celeste style: a fall costs the climb back to the lamp, never the tower, and the honest clock keeps running either way. Eight new section shapes break the ladder rhythm: mid-lane weaves, staircase runs, forked routes, long galleries you sprint across, wall-hugging spires, pendulum swings, and stacked planks you hop up through. And the curve follows Mario's four-step rule: each mechanic is introduced somewhere it cannot easily kill you (a lone shard beside a wide rung, a chimney with a safety plank halfway up the kicks) before the towers start combining them in earnest. Every tower re-certified from scratch under the new physics.
- 2026-07-20·The scaffolding comes down: six towers, each shipped with a corridor certificate, and the taller ones still in the mine, joining the ladder as they pass. Behind them, three instruments. The surveyor climbs rung to rung like a person, resting between moves. The rigger slackens its lines: stutter inputs pruned, every jump held past its apex, every boundary centered in its feasible window. And the tremor test shakes the result, hundreds of seeded replays per rest with every airborne input slid by up to two frames at once; the plaque on each tower reports the tightest window and the worst summit rate it measured. First certificates: every input tolerates at least a 33 millisecond window. Plus ghosts of the certified line and your best climb, a daily tower, and run codes that replay your whole ascent, falls included.