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

This is a submission for the June Solstice Game Jam . What I Built Bletchley's Longest Day is a browser-based cipher escape game set inside a fictional Bletchley Park night shift. The player has to stop a U-boat convoy attack before dawn by clearing five rooms. Each room contains three escalating locks, so the full escape requires 15 solved puzzles . The game combines Caesar shifts, A1Z26 number decoding, Morse, anagrams, fragment ordering, a visible countdown timer, mistake penalties, hint penalties, account-based score saving, and a best-score leaderboard. The solstice theme became the core dramatic clock: night is running out, first light is coming, and the player has to decode the final signal before dawn. Video Demo The demo shows the opening briefing, the three-lock room flow, the Gemini hint penalty, and the final victory state that only appears after all 15 locks are cleared. Live game: https://bletchleys-longest-day.onrender.com 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: Three locks per room : each room has to be solved in stages, so the player earns the escape instead of clicking through one answer. Time as score pressure : wrong answers and hints cost time, while clean solving preserves the best leaderboard run. 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 offi