This page is the engine's proof, and the proof runs in two sizes. Each demo below makes one claim in its smallest honest form, live in the page — and the SOURCE panel under each one is the receipt: change a number, hit RUN ▶, and the claim re-proves itself with your code in it. Then each claim points at the full game it grew into, because a skill you can only demo isn't a skill. Click a game to give it the keyboard.

What's grown since this page was young: characters carry full pose animation and frames-as-JSON, combat is a data table with stances, cooldowns and the Mario stomp, every death plays a departure, enemies pour from destroyable generators, fans blow you over the unjumpable, and two players share one screen. All of it is in these same modules, and all of it is one import away.

1 · Skill: a character that feels right — in thirty lines

The claim: running and jumping that feels like a real game costs almost nothing — and neither does a place: a sky in three data lines, grass and flowers at one legend line each. Still readable top to bottom.

Grown up: every knob on a slider in the Movement Lab; ten named schools in profiles.js, Wizball to Myrtle.

Move with ← →, jump with Z / Space / ↑. → How it's built

2 · Skill: a complete game loop — goal, danger, win

The claim: the gap between "a character in a room" and "a game" is three coins and a guardian — and every coin speaks (a Bubbles layer) and glitters where it stood (an Outcomes layer): four lines standalone here, free with a World later.

Grown up: The Manor — four rooms, a clock, and a vault with demands.

R restarts. → How it's built

3 · Skill: floors with personalities

The claim: one line in a legend gives a tile a behaviour. Belts drag, floors crumble, ladders climb, ice refuses to stop you, and a toadstool trampolines — you spawn on the crumbling shelf, so the proof starts under your feet.

Grown up: Sisters of the Crown's Static Storm — updraft fans over spikes no jump crosses.

↑↓ to climb, R to reset. → How it's built

4 · Skill: everything at once, and effects at the exact point of contact

The claim: the engine's parts compose. Ice into lava into turret fire into a chaser into a springboard — now with a pendulum keeping time overhead, acid dripping from the pipework, and an updraft fan easing the last climb — and every impact throws sparks exactly where it happened.

Grown up: every death now PLAYS — the Outcomes layer gives any body a departure, in every World, automatically.

Jump again in mid-air to double-jump. R restarts. → Build your own in the Map Editor

5 · Skill: worlds bigger than one screen

The claim: rooms connect into worlds with a doorway and a flick — and the world remembers. Coins stay collected everywhere; guardians reset per room. And notice what the code doesn't wire: the "+100" bubbles, the coin sparkles and the victory lap all come free with the World.

Grown up: Myrtle the Turtle — sixteen screens, vine shafts between floors, a nest with demands.

The doorway is on the right. → How it's built

6 · Skill: the same engine, played from above

The claim: one line — movement: 'topdown' — tips the whole engine ninety degrees. No gravity, 8-way running, a sword whose reach depends on whether you're moving — and two hunting philosophies in one maze: a hand-rolled guard beside an engine-native Stalker (who dies as a little ghost, per his Death style).

Grown up: The Undercroft — four floors of Gauntlet, generators pouring stalkers, and a partner on WASD.

← → ↑ ↓ to run (diagonals work), Z / Space / X to swing. → How it's built

7 · Skill: a fight that is data

The claim: an entire combat system — a flying kick, a roar that shoves and stuns, the Mario stomp — is three rows of a table, and the game's only combat code is a listener that counts the felled. The yard now restocks itself (a Generator pours fresh dummies), and each dummy dies in a different style — burst, pop, ghost: the Outcomes shelf, live.

The moveset reference → See it grown up — Myrtle the Turtle →

8 · Skill: a different genre entirely

The claim: the same rooms, stitched instead of flicked, plus a camera that advances on its own, make a scrolling shoot 'em up — no new engine, just a different way of holding it. Don't get crushed. Secure the core.

Grown up: Sector Run with the crush, and Chopper Run's free-scrolling jungle — plus the Designer's waves mode for the fixed-screen school.

Steer with ← → ↑ ↓, hold Z / Space to fire. → How it's built

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Convinced? The games are these seven skills at full size — and the Map Editor hands you all of them without writing code. If you'd rather build than browse: a complete fight game, in two hours.