What I Built

SOLSTICE is a juicy, single-file browser arcade game about the longest day of the year — and a tribute to Alan Turing, born in June, the man who turned the longest nights of a war toward dawn.

You are a spark of light. Move with your mouse (or finger) and the whole world responds: the sky shifts from blazing noon to deep night, the sun rises and sets with your daylight, particles burst and the music speeds up as the danger climbs.

🌗 Daylight is your health. Gather the sun's motes to keep it burning; touch a shadow and the night creeps in. Let it hit zero and the screen pulses red as night falls.

🌀 The Solstice Turn. At the midpoint the world flips — the longest day becomes the longest night (exactly the prompt's "longest day for half the world, shortest for the other"). The sky goes cold, the sun becomes a moon, and light becomes precious.

🌑 Two bosses. The Longest Night at day 10, and the bigger, faster, bullet-spitting Eclipse King at day 20 — each with a phase-2 rage mode and a codebreaking finisher.

☄ Power-ups & a stockpile-able Nova. Time Warp, Light Magnet, Freeze, Sun Fragment — plus the Sun Nova you can bank ×3 and unleash to wipe the screen.

It connects to the theme on every axis: the solstice (longest day, the Turn), light vs. dark as the core mechanic, and Alan Turing woven into the story and the boss fights.

Code

The whole game is one index.html — no build step, no dependencies, no external assets.

stackmasteraliza / solstice-cipher

SOLSTICE — feed the light, hold back the night. A 20-level arcade game for the June Solstice Game Jam, an ode to Alan Turing.

☀ SOLSTICE

feed the light · hold back the night

A juicy 20-level arcade game for the June Solstice Game Jam — and an ode to Alan Turing.

The longest day of the year, and the dark wants it back. Glide your light, gather the sun's motes, grab power-ups, survive the Solstice Turn, and break two beasts of night.

▶ Play it live · 🎬 Watch the demo · Power-ups · How it's built

✨ Why it's fun

You are a spark of light. Move with the mouse (or your finger) and the whole screen responds — the sky shifts from blazing noon to deep night, the sun rises and sets with your daylight, particles burst, combos chime, and the music speeds up as the danger climbs.

🌗 The light is the game. Daylight is your health bar. Gather motes to keep it burning; touch a shadow and the night…

View on GitHub

How I Built It

Plain HTML5 Canvas + vanilla JavaScript. A few decisions I'm happy with:

One variable drives the whole atmosphere. The sky, the sun's arc, the glow and the star field are all tied to a single value (--night, 0 = blazing noon → 1 = full dark). The game loop just sets it from your remaining daylight and everything follows — the sun literally sinks as you run out of light.

All audio is synthesized live with the Web Audio API — no sound files. There's a kick/hi-hat/bass beat track that speeds up every level, a separate furious minor-key boss track, win/lose stingers, and reactive SFX whose pitch rises with your combo.

20 levels, two bosses, a power-up economy, and four enemy types (normal, fast darters, heavy tanks, and splitters that break in two) — all from a compact entity loop.

Honest Mastermind scoring for the Turing finisher, with correct duplicate-glyph handling (the classic trap), unit-tested against the tricky cases.

Onboarding built in: a guided practice with tooltips the first run, and a boss briefing before each beast, so a new player (or a judge) is taught every mechanic right before they need it.

Accessible & portable: fully keyboard + touch playable; colour and shape pairing for enemies; runs from a single file anywhere.

Prize Category

🎯 Best Ode to Alan Turing.

June is Turing's birth month, so the game is built around the thing he's famous for — code-breaking and the triumph of logic over darkness:

Mechanic: each boss can't just be hit to death. At zero HP it's exposed, and Turing's Bombe reveals a cipher — you "Decode the Dawn" by repeating the sequence to break the night for good. Code-breaking is the finishing move.

Narrative: between-level "transmissions" trace his arc — Bletchley, the Enigma, his persecution for who he loved, "never granted his own daylight." The win screen, DAWN, is a tribute: "For Alan Turing (1912–1954) — who broke the world's hardest cipher and was never allowed his own daylight."

Design: the Enigma rotor motif and the light-vs-shadow (1s and 0s) framing run throughout.

Not submitting to Best Google AI Usage — no Google AI is used in this build.

Thanks for running the jam — happy solstice! ☀

DEV Community

SOLSTICE — feed the light, hold back the night (an ode to Alan Turing)