Emberfall

What it is. You are a guttering ember falling down a vast, cold flue, trying to reach the hearth at the bottom before you go out. You have exactly one verb — a flare-kick — and it does three things at once: it lights a radius so you can see, it launches you in a chosen direction, and it burns fuel you can’t get back. Between flares you fall in the dark. The whole game is the rhythm of flare → read → commit, over and over, deeper.

Player fantasy / why it’s fun. Not “a platformer in the dark” but “I am a small light trying to stay lit long enough to get home, and every time I look, I spend myself doing it.” Mastery is learning to flare late enough to conserve, early enough to survive — reading a hazard in the half-second of light and committing to a trajectory before the dark closes back in.

The brief

Celeste but your dash is your only lantern — and your lantern is your fuel. One verb that is sight, motion, and life at once.

The spine

Descend a lightless shaft where your only light is your only movement is your only life — mastery of the flare-rhythm.

Part	This game
Objective	Reach the hearth at the bottom of the flue
Superpower	The flare-kick — burst that lights a radius and launches you a chosen direction
Scarcity	Fuel (each flare burns embers = life) + commitment (light fades in ~1s; the launch can’t be cancelled) + the constant fall in the dark between flares
Obstacle	Soot-chokes that snuff you, wet walls that douse a flare, updrafts, dead-end geometry — all invisible until lit
Renewal	Procedurally-segmented flue; each segment introduces one new element that recombines with the flare (updraft, damp, crosswind)

Resonance

Every element traces to the spine. This table is the coherence proof — see process-the-spine.

Element	Arrow back to the spine
Verb: flare-kick	The single agency; sight, motion, and spend fused into one input
Power creates the problem	Flaring lights and commits your arc before the dark returns and burns the life you’re trying to preserve → looking, moving, and dying are the same act (passes the gate)
Scarcity: fuel = life	The flare isn’t free, so when to look is the whole decision
Renewal: one new element per segment	Re-poses “read-and-commit in one beat” against a fresh interaction each time
Death-handling: instant relight at last hearth-checkpoint	Spine is retry-mastery; a punishing death would be dissonant (`antipattern-dissonance`)
Setting: falling down a cold house-flue toward the hearth	Objective made physical — going home before you go out
Theme: holding a dying light	The mechanic (spend yourself to see) is the metaphor (a small flame’s last errand)
Feel: warm bloom in the lit radius, near-silence in the dark, frame-tight launch	Mastery demands failure be yours; the dark must feel fair, the light must feel precious ([[design/JUICE.md]])
Fuel pickups: stray embers glowing faintly in the dark	The one thing worth flaring toward — reward and risk on the same axis (`pattern-risk-reward`)

No row is decoration; no row fights the spine. The gate holds: you cannot see without spending the life you’re trying to save.

The twist applied — constraint

The bend that found this spine is a hard constraint (see process-the-twist as the sub-tool of process-the-spine): the light source, the movement, and the life bar are one resource. Collapse three systems most games keep separate — vision, locomotion, health — into a single verb, and the loop falls out on its own. Don’t add a second light or a jump; the constraint is the game.

The three pillars

Fall out of the spine. Cut anything serving none — see process-pillars.

One verb, three meanings. Flare = see + move + spend. If you ever add a free look or a free jump, you’ve broken the spine. Guard antipattern-feature-soup.
The dark is fair. Everything lethal is readable in the flare before you commit. A hazard you couldn’t have seen is antipattern-input-lie, not difficulty. Lean on system-telegraphs and pattern-readability.
Mastery, not attrition. Death is instant and cheap; the loop rewards a better rhythm, never grinding fuel. Guard antipattern-fail-loop-tax and antipattern-grind-wall.

Scope & first playable

Ruthlessly minimal. One vertical shaft, one hazard type, fuel that is visible.

Layer	First playable	Deliberately deferred
Verb	flare-kick: lights radius r, launches on aim, burns 1 fuel	charge-flares, wall-kicks, glide
Fall	constant downward drift; dark between flares	horizontal chambers, moving flue walls
Scarcity	fuel bar = life; 1 flare = 1 fuel; hearths refill + checkpoint	fuel economy, hoarding decisions
Obstacle	one hazard: soot-choke that snuffs you on contact	wet walls, updrafts, crosswind
Renewal	3 hand-built segments proving read-and-commit	`system-procgen-design` segment generator
Show	warm bloom in-radius, hard black out-of-radius, ember particle on flare	screen-shake tuning, music bus

The one beat the first playable must earn: the held breath before a flare — the player hesitating because looking costs life. If that half-second of tension isn’t there with one hazard, more content won’t add it. Avoid antipattern-content-desert: prove the flare-rhythm, then generate depth.

Determinism is the hard constraint. The flue segments, hazard placement, and any drift all roll through the world’s deterministic RNG so a seed replays the same descent — the retry-mastery loop depends on the run being the same run. Keep the bloom/particle layer pattern-readability-clean and cosmetic; it never enters world.hash(). See system-save-and-checkpoint for the hearth checkpoints.

Handoff

A design isn’t done until it names its proofs.

design/FUN.md law 8 — the ablation proof. Build the descent twice: coupled (flare burns fuel) and ablated (free light). Run a skilled pilot and a lazy one over both; assertLoadBearing({ coupling: 'flare-cost', coupled, ablated, skilled, lazy }) must show the skill-gap collapse when the cost is removed. If free-light plays the same, the held-breath was never real and the coupling is a lie.
design/JUICE.md — the entire feel rests on the light/dark contrast and the preciousness of the flare. This is a feel proof, not a numbers proof.
Coherence gate — the Resonance table above must stay complete; any new system needs a row or it’s antipattern-decoration.

Then design your own committal-single-resource spine — don’t reskin this one. See process-refine-and-handoff.

This module rendersthe repo's markdowndirectly — edit it there, it changes here.