--- title: "The Cradle: Episode 01" url: "https://aigamehub.app/en/games/i-built-a-custom-horror-game-engine-with-claude-code-in-4-we-15a00b" source: "https://www.reddit.com/r/ClaudeCode/comments/1x3pqx7/i_built_a_custom_horror_game_engine_with_claude" source_type: "reddit" play_url: "https://0xkot.itch.io/the-cradle-episode-01" platform: "both" login_required: false pricing: "free" origin: "original" ai_tools: ["Claude Code"] game_languages: [] author: "EconomyPrudent6511" author_handle: "EconomyPrudent6511" category: "Action" categories: ["action", "adventure"] tags: ["browser", "first-person", "horror", "itch.io", "solo-dev", "three.js"] added: "2026-10-16T17:11:53.799Z" updated: "2026-10-16T17:11:53.799Z" locale: "en" content_locale: "en" --- # The Cradle: Episode 01 A free browser-based narrative horror game by a solo developer: explore corridors and rooms, find keys, read notes, hide from a creature that hunts you, and survive scripted scares, power cuts and lifts. Runs in the browser via three.js and also on phones. ## Description The Cradle: Episode 01 is a first-person narrative horror game built on the developer's own Narrative Horror Runtime engine and rendered with three.js, so it plays directly in a browser (and on phones) with no install; Windows and Steam Deck builds also exist. Play involves moving through corridors and rooms, finding keys to open locked doors, reading notes, using hiding places, and avoiding a creature that hunts the player, with scripted scares, power cuts and working lifts. The author states the game is free and that most of the code was written with Claude Code. A second, shorter Halloween side game, The Cradle: Trick-or-Treat, is also linked from the same post and is playable in the browser. ## Original post I built a custom horror game engine with Claude Code in 4 weeks. 200+ people have played the games and 7 streamers have streamed them Four weeks ago I had an empty folder. Today there's a custom horror game engine, two games live on itch.io , 200+ players, and 7 streamers who've played it on stream. I'm a solo dev, and most of the code was written by Claude Code. Here's how it actually went. What I built NHR (Narrative Horror Runtime): an engine made for one genre only, narrative horror. Corridors and rooms, locked doors and keys, notes, hiding places, a creature that hunts you, scripted scares, power cuts, lifts. It runs in the browser on three.js, phones included, and ships as Windows and Steam Deck apps too. On top of it, the tooling: a map compiler: write a level as YAML, get a 3D map a 2D room planner: draw rooms in metres, round halls, stairs, working elevators a 3D editor: one-click "dress this room", props, lights, story triggers, doors and keys real ray-traced light baking on a GPU box (Blender Cycles, driven remotely) an original score and sound effects, all generated in code The numbers Started 15 September. 866 commits and 227 merged PRs since. Episode 01 went from first file to playable on itch in under two weeks. The Halloween side game, Trick-or-Treat, took 3 days from first file to live. 7,000+ automated tests, including a full QA of every level: every key can be reached before its door, every room can be walked to, nothing flickers. 200+ players, 7 streamers, and so far the feedback has been really positive. How I worked with Claude Code Plan first, then build. I describe what I want, Claude proposes a plan, and I approve or change it before anything is written. Parallel agents in git worktrees. Often 2–3 at once: one on the level editor, one on a bug, one on a release. Each opens a PR, and I review screenshots and merge. Everything is text. Levels, stories and placements are YAML, JSON and Python, so every AI change is a diff I can read and reject. A LESSONS.md file. Every bug class we ever shipped, plus the rule that now prevents it. Claude reads it before planning, and the same mistake rarely happens twice. The tests are the safety net. Agents prove a fix with headless playthroughs, pixel diffs and before/after screenshots, not just "should work". Things I learned the hard way Tell it about your environment. My Mac must never run Blender with GPU rendering (it crashes), so all Blender work runs on a separate Linux GPU box. And games play sound, so every in-game test runs headless and muted, or I'd hear horror screams at 2 am. Guard your hardware. I run a local LLM on the same GPU, and a bake once silently fell back to the CPU after a driver update broke. Now every bake script checks the GPU and free VRAM first. Small stacked PRs beat one giant one. The editor UI refactor went in as 5 stacked PRs, each tested on its own. Here's a 60-second video of a whole level going from a blank page to playable with these tools: https://www.youtube.com/watch?v=uoYc_QS2bSo Play the games (free, in your browser, no install): 🎮 The Cradle: Episode 01: https://0xkot.itch.io/the-cradle-episode-01 🎃 The Cradle: Trick-or-Treat: https://0xkot.itch.io/the-cradle-trick-or-treat Happy to answer anything about the workflow, the engine or the prompting. And if you play it, I'd love to hear what scared you. 👻 submitted by /u/EconomyPrudent6511 to r/ClaudeCode [link] [comments]