# Solstice — A Light-Routing Puzzle Game > Source: > Published: 2026-06-21 17:15:40+00:00 *This is a submission for the June Solstice Game Jam* **What I Built** Solstice is a puzzle game where you place mirrors to guide light beams across a grid. Each level has two modes — SUN and MOON. You toggle between them to route both beams to their targets. Both need to be lit at the same time to win. Click a cell to place a `/` mirror, click again for `\` , again to remove. Right-click removes it. Ctrl+Z to undo. That's the whole mechanic — but the levels get hard fast. There are 18 levels split into 7 tiers. It starts simple (one mirror, one beam) and builds up to puzzles where you have fewer than 10 free cells and every placement has to count. I verified every level with a Python solver to make sure they're all solvable at the stated par. The game has a terminal with a Bletchley Park theme. You get 3 questions, the AI responds like a trapped wartime consciousness, and at the end you decide if it was human or machine. It connects to the Gemini API if you have a key, otherwise it uses pre-written responses. **VIDEO DEMO** {[https://youtu.be/gqtylwILuJ8](https://youtu.be/gqtylwILuJ8)} Code **A light-routing puzzle game with a custom ray-tracing engine, dual-spectrum beam physics, 18 levels across 7 tiers, a CRT terminal narrative, undo/redo, and a star-based rating system.** Built with vanilla JavaScript, rendered on HTML Canvas 2D, with audio synthesis via the Web Audio API and optional AI-powered dialogue through Google Gemini. Deployed as a static site on the Vercel CDN. Each subsystem is a standalone ES module communicating through a central game state, orchestrated by a `requestAnimationFrame` game loop. ``` flowchart LR subgraph Pipeline[Core Pipeline] direction LR GL["GAME LOOP
main.js
requestAnimationFrame
renderer.draw()
updateUI()"] RT["RAY TRACER
raytracer.js
Dual-pass simulation
SUN + MOON paths
Cycle detection"] RD["RENDERER
renderer.js
3-pass canvas draw
Glow + dashes + pulses
Particle integration"] PS["PARTICLES
particles.js
emit() / burst()
update(dt) / draw()
Lifecycle management"] end GL --> RT --> RD --> PS style GL fill:#1a1a3a,stroke:#ffd700,color:#ffd700 style RT fill:#1a1a3a,stroke:#4a90d9,color:#4a90d9 style RD fill:#1a1a3a,stroke:#7b68ee,color:#7b68ee style PS fill:#1a1a3a,stroke:#00ff88,color:#00ff88 style Pipeline fill:#0a0a1a,stroke:#333,color:#888 flowchart TB subgraph Systems[Supporting Systems] direction TB IM["INPUT
input.js
Mouse + ``` …Play it here: [https://solstice-game-pi.vercel.app](https://solstice-game-pi.vercel.app) **HOW I BUILT IT** Vanilla JavaScript with HTML Canvas for rendering. No frameworks, no libraries — just ES modules and the Canvas 2D API. The ray tracer uses grid-based ray marching. Each frame runs twice — once for SUN, once for MOON. Mirrors transform the direction vector: `/` does `[dx, dy] → [-dy, -dx]` , `\` does `[dx, dy] → [dy, dx]` . Cycle detection prevents infinite loops from mirror pairs facing each other. Audio is all Web Audio API oscillators — no sound files at all. The terminal uses the Gemini API when configured, with a system prompt that keeps the Bletchley persona consistent. Levels are hand-designed with increasing wall density. Levels 11-18 went through multiple redesigns after my Python solver kept finding unintended shortcuts. **Prize Category** BEST ODE TO ALAN TURING ; The terminal is a Turing Test. You talk to something that believes it was a code-breaker at Bletchley Park in 1945. Three questions, then you judge. The dialogue touches on Enigma, ration books, the hum of valves. The ending asks the same question Turing posed — can you tell the difference? Best Google AI Usage The terminal connects to the Gemini API for dynamic responses. The AI stays in character as a wartime consciousness. Without a key it falls back to pre-written dialogue, but with Gemini every conversation is unique.