This is a submission for the June Solstice Game Jam
What I Built
Solstice Cipher: Enigma of the Longest Day is a browser-based puzzle game built around the Caesar cipher — the same substitution cipher technique used in ancient cryptography. On the theme of the June Solstice, I tied the longest day of the year to an Enigma Machine-inspired challenge: decode encrypted messages before time runs out, with the difficulty scaling as the sun climbs higher.
The game features a real-time animated sky that shifts through dawn, noon, and dusk to reflect the solstice theme. Players are given a cipher shift key and must decode encrypted phrases by working through the Caesar cipher manually or by reasoning out the pattern — no brute-force tools allowed in-game.
This connects to the June Solstice theme because the game is literally set on the longest day: the puzzles grow harder as the day progresses, and the sky animation mirrors real solstice light from sunrise to sunset.
Video Demo
Play it here:
Code
GTXPOFFIC-developer
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Solstice-Chiper-Enigma-of-the-Longest-Day
This is a Enigma based June Solstice game feel free to include your own code or tinker this project just mention the orignal developers name pls
Solstice Cipher — Enigma of the Longest Day
A browser-based Enigma machine puzzle game set on the June solstice. Decode (or encode) encrypted transmissions before the daylight runs out.
Built By
Sudipto — Original developer
Feel free to fork, tinker, and include this in your own projects. Just mention the original developer's name.
How to Play
Objective
Configure the Enigma machine correctly to decode each level's ciphertext (or encode the plaintext) before the sun sets. Each wrong guess costs 45 minutes of daylight; correct guesses pause the timer for 30 seconds.
Controls
| Control | What it does |
|---|---|
| Rotor dropdowns | Select which 3 rotors (I–V) are used |
| ▲ / ▼ buttons | Adjust each rotor's starting position |
| Plugboard | Drag from one letter to another to connect them with a coloured wire (swaps those letters inside the machine) |
| Keyboard | Type the highlighted letter — click on-screen or use your physical keyboard |
| Lampboard | Lights up |
How I Built It
I built Solstice Cipher entirely in the browser using vanilla HTML, CSS, and JavaScript — no game engine needed.
Key technical highlights:
- Caesar cipher engine — a pure JS implementation that encodes and decodes strings using a variable shift key, supporting both encoding and player input validation
- Real-time sky animation — a CSS + JS canvas animation that simulates the solstice sky, cycling through morning, noon, and evening gradients in sync with puzzle progression
- Enigma-style onboarding — I embedded a Jared Owen Animations explainer video on the Enigma Machine so players unfamiliar with historical cipher machines can get up to speed quickly before diving in
The biggest challenge was balancing the puzzle difficulty curve — making early ciphers approachable while keeping late-game decoding genuinely challenging without feeling unfair.
Prize Category
Best Ode to Alan Turing — Solstice Cipher is directly inspired by Alan Turing's work breaking the Enigma cipher during WWII. The game pays homage to that history by putting players in the seat of a codebreaker on the longest day, using the same Caesar substitution principles that Turing's work built upon. The Enigma Machine explainer in the onboarding is a deliberate nod to that legacy.
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