Wall Jump

What it is. Press jump while pressed against a wall to launch up-and-away — off the surface, gaining height. Alternate walls in a shaft and you climb a space with no floor. It converts a vertical gap into a rhythm the player performs, not a distance they cross.

Player fantasy / why it’s fun. “The wall isn’t stopping me — it’s my next foothold.” The zip up a narrow chimney, the last-second stick before a fall, the descent turned into a controlled scramble. Walls stop being dead ends and become the terrain.

The verb

Touch a wall while airborne → hold toward it (or auto-stick) → press jump. You leave the wall with a fixed push-off vector: outward so you clear the surface, upward so you gain. The core dyad is cling, then kick — the wall is a beat, not a rest.

How it feels / why it’s fun

Momentum you author. Unlike a ledge grab that parks you, the wall jump keeps you moving — height is earned in a continuous scramble, never a pause.
Rhythm under pressure. Alternating a shaft is a metronome; miss the beat and you fall. That cadence is where mastery lives (pattern-mastery-and-flow).
Recovery, not just ascent. A mistimed jump can still be saved by catching a wall — grace on the way down feels generous and skillful at once (system-grace).
The read is the skill. Which wall is climbable, from which side, at what angle — legible walls turn a fall into a plan (pattern-readability).

Tuning levers

Lever	What it changes	Sane default
Push-off X	Horizontal launch off the wall	~0.7–1.0× run speed
Push-off Y	Height gained per kick	~0.85× a floor jump
Wall-stick time	Frames you cling before sliding	6–10 frames (a beat to react)
Wall-slide speed	Fall speed while clinging	~40% of terminal velocity
Wall coyote	Frames after leaving a wall you can still kick	4–6 frames
Input lockout	Frames after kick before you re-steer toward the wall	8–12 frames (stops instant re-cling)
Same-wall cooldown	Can you re-kick the wall you just left?	No, until you touch a different surface

The input lockout is the anti-cheese lever: without it, holding into the wall lets a player mash jump and levitate up one surface — an antipattern-input-lie where the geometry implies a limit the code doesn’t enforce. Lock out re-steer for a few frames so each kick commits to leaving.

Infinite-climb prevention is a design decision, not just a bug fix: either the input lockout (you drift away before you can re-cling), a same-wall cooldown (a kicked wall is inert until you touch another), or a per-kick vertical decay (each same-wall kick gains less). Pick one and make it visible — a scuff mark, a fading grip — so the limit reads as rule, not glitch.

Slots into (genres + anchors)

genre-precision-platformer — the home genre. Celeste (anchor-celeste) makes the wall-slide + climb the spine of its movement and its skill ceiling.
genre-metroidvania — as a gated traversal unlock (system-progression): the shaft you saw hour one, climbable hour three. Pairs with mechanic-double-jump and mechanic-dash.
genre-puzzle-platformer — walls as a spatial resource to ration (see the crumble twist below).
genre-action-adventure — Dead Cells (anchor-dead-cells) folds wall-cling into fast combat traversal.

Composes tightly with mechanic-wall-run (horizontal sibling), mechanic-ledge-grab (the resting counterpart), and mechanic-glide (descend the height you climbed).

Twist seams

Wall jump but each wall can only be kicked once (constraint) — a wall spends on contact and goes inert (grip mark, color flip). A shaft becomes a route puzzle: order and reach matter, backtracking is denied. Turns free traversal into a genre-grid-puzzle-flavored plan against mechanic-double-jump for recovery.
Wall jump but the wall crumbles behind you (structure) — the kicked surface breaks a beat later, removing the return path. Forces continuous forward rhythm and one-way ascent; a fall means a full restart of the shaft. Escalates tension the higher you climb (pattern-pacing-and-tension).
Wall jump but the walls are moving (scale) — sliding or rotating surfaces make the timing of the kick the whole challenge, not the aim. The metronome now has a moving beat.

How it wires to Hayao

Collision + input are engine-generic: detect a wall contact on the airborne body, read the jump press, apply the push-off vector. The scene tree holds the walls; the body’s velocity is what you set on kick.
Wall-stick, coyote, and lockout are frame counters on the player state — count in fixed sim ticks so behavior is deterministic and replayable; never wall-clock time.
Feel first in isolation. Prototype the push-off vector, stick-time, and lockout in a single-mechanic lab before wiring it into a level — see the platformer movement material in sandboxes/ and the logic/view split in examples/sokoban/. Tune in a lab, then port.
Climbable walls need a readable tag in the level data — a surface property the level author sets, and the view renders distinctly (a texture, an edge highlight). Don’t infer climbability from geometry; author it, so the rule and the picture always agree.

Fails when…

Infinite climb leaks. No lockout/cooldown → hold-into-wall + mash = free flight. The mechanic loses all its rhythm and cost.
Climbable walls aren’t legible. The player can’t tell a foothold from décor, so every shaft is trial-and-death — an antipattern-input-lie of the eyes (pattern-readability).
No grace on the cling. Zero wall-coyote and a tight stick window makes correct inputs feel dropped (system-grace); the fall reads as the game’s fault, not the player’s.
Push-off fights the camera. Launch away from a wall the camera hasn’t shown yet and the player leaps blind — pair the vector with lead room in the view.
It’s the only verb. A whole game of shafts is monotone; wall jump shines as one tool in a movement kit (system-mastery-curve), not the entire kit — beware antipattern-content-desert.