Same brief, different models

# Splash Olympics: the brief

Build **Splash Olympics**, a browser game in tribute to *Dolphin Olympics*, the Flash-era game where you dive deep, build up speed underwater, burst out of the pool and do flips in the air. It will be published on a website about AI, played by curious adults on a computer or a phone. Most of them will play for a few minutes. Make those minutes great.

The sections below describe a version that has already been played and refined over several rounds, plus a few technical requirements added so every version can be published the same way. Treat them all as requirements. Everything they don't decide is yours: art style, how the dolphin looks, the jokes, extra easter eggs, extra polish. Aim for the version you'd be proud to ship, with a beautiful first frame, a game that feels satisfying in your hands, and a sense of humour.

## The fantasy

You're a dolphin in a pool. You swim down, turn, and race up to the surface as fast as you can. You burst out of the water, spin through flips, and dive back in nose first, cleanly. Every clean dive makes your next jump more powerful, so a good run climbs from a few metres above the pool to the clouds, to space, past the planets, and finally to a diner at the end of the galaxy.

## Core loop and physics

- **Underwater:** holding "swim" pushes the dolphin forward in the direction it faces. Left and right rotate it. A dolphin doesn't drift sideways: its movement follows the direction it faces, with water drag and a slight upward buoyancy.
- **Launch:** leaving the water fast enough makes the dolphin airborne. Too slow, and it just bobs at the surface.
- **In the air:** gravity takes over. Left and right spin the dolphin quickly, so you can flip. Front flips and back flips are counted separately, relative to the direction of travel.
- **Re-entry:** what matters is the angle between where the dolphin points and where it's moving.
  - A **clean dive** (nose roughly along the direction of travel) scores and charges your jump power.
  - A **perfect dive** (very close to exact) scores more and charges jump power more.
  - Anything else is a **belly flop**: it costs jump power, resets your combo and plunges you deep, so watch the floor.
- **Jump power:** a multiplier on launch speed. It grows with every clean dive (more for perfect ones) and shrinks on a belly flop. It's what turns a run from metres into space, so the progression must be felt.
- **The pool floor:** touching the sandy bottom with any real speed ends the game.
- **The clock:** five minutes for the whole game. When time runs out mid-jump, the game ends when you land.

## Scoring

Score each jump on height, air time and flips; more flips per jump should be worth disproportionately more. Then apply the entry:

- clean dive: the jump scores;
- perfect dive: ×1.5;
- front flips and back flips in the same jump: another ×1.5;
- belly flop: nothing.

A combo multiplier grows with each clean landing that included flips (cap it) and resets on a belly flop. Reaching altitude milestones pays a bonus, and flying through objects in the sky pays points (easter eggs pay more).

## The journey upward

The sky changes with altitude, from blue to deep blue to black, with stars appearing and the Earth's curve showing once you're high enough. In order, roughly:

1. Seagulls.
2. Hot-air balloons, in several clearly different designs.
3. Passenger planes at cruising altitude.
4. Weather balloons in the stratosphere.
5. The edge of space: satellites, then astronauts.
6. Leaving Earth's orbit (a big bonus), UFOs.
7. The Moon, Mars, Jupiter, Saturn, Uranus (it deserves a joke), Neptune, Pluto ("still a planet to us"), with comets in between.
8. At the very top: **the Diner at the End of the Galaxy**, with a neon sign and the line "So long, and thanks for all the fish".

Altitude shows on screen in metres and then kilometres. It doesn't need to be to scale; it needs to feel enormous.

## Easter eggs

These must be in the game, as things you can fly through for points:

- the Hubble Space Telescope;
- the ISS (wave at the crew);
- a falling whale and a bowl of petunias ("Oh no, not again");
- a towel that says "Don't panic";
- a red roadster with a spaceman at the wheel;
- Voyager and its golden record;
- Russell's teapot, in orbit;
- a bonus when the altimeter reads 42 (you pick the unit), for "the answer to everything".

Add your own if they're funny.

## Camera

These came out of playtesting:

- **Zoom out the faster you fly**, so you can see how high you are and the things you pass. Don't speed up time instead: the easter eggs must not blur past.
- **Always keep the dolphin in frame**, at any speed and height, including the long fall from the top.
- **When falling fast, keep the dolphin in the upper part of the screen**, so you can see the water coming.

## Balance

Also from playtesting:

- The fall back to Earth must not be too fast to enjoy.
- It must be possible to lose. Keep the margin for a clean dive tight enough that a careless dive is a belly flop, and make the pool floor a real danger.
- A skilled player can reach the Diner within the five minutes. A first game usually won't.

## Records and feedback

- A **local top-5 leaderboard**: score, highest altitude and date. Show it on the title and game-over screens.
- Live alerts during play: when you're close to your record (within 20%), when you enter the top 5, and when you beat your record.
- Pop-up text for flips, dive quality, combos, milestones and easter eggs.
- The game-over screen shows the reason (sand or time), the score, the highest altitude and your rank.

## Sound

Every sound is synthesized live with the Web Audio API; there are no audio files. At least: splashes (small and big), the launch, flips (front and back sound different and rise in pitch as they add up), clean and perfect dive chimes, the belly flop, the bonk on the pool floor, pickups, an easter-egg jingle, milestones, bonuses, a record fanfare, warning ticks in the last 10 seconds, game over, bubbles while swimming, and wind that rises with speed. Audio starts only after the player's first click, tap or key press. There's a mute toggle (the M key and an on-screen button), and the game remembers the choice.

## Controls

- **Keyboard:** Left/Right arrows or A/D to rotate. Up arrow, W or Space to swim. Enter or Space starts and restarts (a key still held down from play doesn't count, so the game-over screen stays up). P pauses, M mutes.
- **Touch:** on-screen buttons to rotate left, rotate right and swim, big enough for thumbs. Tap to start and restart.
- A click or tap also starts and restarts. Show the touch buttons on touch devices only; on a computer you play with the keyboard.

## Technical requirements

These are new for this comparison, so every version can be hosted the same way. They're fixed:

- **One self-contained HTML file.** All CSS and JavaScript inline. No libraries, no external requests of any kind, no web fonts, no image or audio files. Draw everything in code on a canvas (HTML elements for buttons are fine).
- **Smooth:** aim for 60 frames per second on an ordinary laptop and phone. Physics must not depend on the frame rate.
- **Every screen size:** it has to work from a 360 × 640 phone in portrait to a large desktop monitor, in portrait and landscape. All text, the HUD and the leaderboard fit on screen. Touch buttons never cover the HUD or other text. No page scrolling or zooming.
- **Storage:** use exactly one `localStorage` key, the one named in the message that came with this brief, for the leaderboard and settings. Wrap all storage access in try/catch: the game must still work when storage is blocked.
- **Pause** automatically when the tab is hidden.
- **Reduced motion:** with `prefers-reduced-motion`, drop screen shake and flashing.
- **State for the website:** keep `document.body.dataset.state` set to `title`, `play`, `paused` or `over`. On the title and game-over screens, keep a strip about 56 px high clear at the top centre; the website shows a small "back" link there.
- **No errors** in the browser console.