Bletchley's Longest Day: a wartime cipher escape game for the June Solstice Game Jam

Code

Repository: https://github.com/himanshu748/bletchleys-longest-day

How I Built It

The game is a lightweight Node-served browser app. The front end is a hand-built HTML/CSS/JavaScript game surface, while server.js serves static files and protects the Gemini API key behind a server-side /api/hint endpoint.

The main design goal was to make the game feel like a tense intelligence desk rather than a generic puzzle page. Every room has atmosphere, evidence props, lock-specific copy, feedback states, and a timer that is always part of the pressure.

The puzzle structure was tuned around three ideas:

1. 
   Three locks per room: each room has to be solved in stages, so the player earns the escape instead of clicking through one answer.


2. 
   Time as score pressure: wrong answers and hints cost time, while clean solving preserves the best leaderboard run.


3. 
   Guest mode vs signed-in mode: guests can play the full game, but Gemini-powered hints and saved leaderboard scores belong to authenticated players.

Google Gemini is used as a server-side hint officer. When a signed-in player asks for help, the game sends Gemini the active lock name, prompt, mechanism, visible puzzle text, failed attempts and hint level. Gemini then returns a short, question-specific nudge without revealing answer words. There is also an answer guard and fallback hint system so the game never depends blindly on model output.

Antigravity helped drive the build loop: implementing, checking, playtesting, tightening responsive UI and iterating on the final submission assets.

For hosting, the game runs on Render. Supabase handles authentication and leaderboard storage so each username has one best score rather than repeated leaderboard spam.

Prize Category

I am submitting for Best Google AI Usage because Gemini is not just decorative here. It is part of the gameplay economy: hints are question-specific, limited, penalized and unavailable to guests.

Antigravity helped drive the build loop: implementing, checking, playtesting, tightening responsive UI, and iterating on the final submission assets. Also veo is used through higgsfield for assets.

I am also submitting for Best Ode to Alan Turing. The game is built around codebreaking under time pressure, Bletchley Park atmosphere, wartime signals, and the feeling of solving small pieces of a larger intelligence picture before the world changes at dawn.

What I Am Proud Of

I like that the game does not treat AI as a free answer button. Gemini is useful, but it costs time and score. The best run still belongs to the player who thinks clearly under pressure.

The final shape feels like a compact escape room: readable enough to play on desktop or mobile, but hard enough that a clean 15/15 run feels earned.