コイン放置防衛
Free · play online in your browser, no download
Blue stick figures hold the base while red ones charge: allies shoot on their own, coins pay for more allies and turrets, five waves and a boss. Built by Claude Code from a detailed spec.
Official site aona0530.github.io, verified Nov 3, 2026. Linked as the playable game (“🎮 コイン放置防衛：https://aona0530.github.io/coincollect/”) in the developer's own Qiita article.
Where to play
Every platform this game is on. Links are checked against official sources; we never host or mirror games.
- Play free — official siteBrowserReleased · One-stage MVPFree
Runs in a desktop browser. No download.
Browser (no download) · Official link verified Nov 3, 2026.
About コイン放置防衛
コイン放置防衛 is a free 3D idle tower defense game for the browser. Blue stick figures defend a base against waves of red stick figures; allies aim and fire arrows on their own, and enemies drop coins that are collected automatically. Between waves you walk your character onto white slots to build turrets (a wooden bow stand, a stone bow stand, a magic cannon) or onto recruitment zones to add archers, spearmen and an archer captain, each costing more than the last, and the base grows from a camp to a fort and beyond as total coins rise. The stage has five waves and a boss; if the base's health reaches zero, everything resets. The developer, aonami, calls it the idle defense game often seen in ads. It was built as a test of a two-step workflow: the developer wrote a detailed requirements document with a chat AI, with every number, wave, cost multiplier and data file spelled out and a minimum scope set, then handed it to Claude Code with the Opus 4.8 model, which had the whole game skeleton running from its first output. The developer then tuned the balance by playing and editing the JSON settings files. The document planned a React Native and Expo phone app, but the developer chose to build it first for the web with React Three Fiber. In Japanese, for PC browsers; progress is saved in the browser.
How it was built
VerifiedThe Qiita article (30 Jun 2026) says the implementation was left to Claude Code with the Opus 4.8 model (“実装側は今回 Claude Code、モデルは Opus 4.8 に任せました”). After the requirements document was handed over, the first output already had the game's skeleton running: 3D stick figures, auto-attack, wave progress and building by standing on a slot (“要件定義書を渡して実装させたら、最初の出力の時点でゲームの骨格…が一通り動いていました”). The developer mentions small follow-up fixes (such as letting the player character shoot arrows too), and says the AI handled the implementation of the specified structure while scope, approach, balance and final checks stayed with the developer. Balance was tuned by changing numbers in the separate JSON files rather than the code. The full requirements document given to Claude Code is reproduced in the article.
Two steps: a requirements document written with a chat AI (concept, units and costs, enemy waves, slot unlocks, base growth, upgrades, save format, with stage, unit, turret, slot and upgrade data split into JSON files and an explicit one-stage, five-wave MVP scope), then implementation by Claude Code (Opus 4.8). Built for the web with React Three Fiber (Three.js) and deployed on GitHub Pages; a React Native and Expo version is planned later.
- Engine / framework
- React Three Fiber (Three.js)
- Languages
- JavaScript
- Team size
- Not disclosed
- Development time
- Not disclosed
- Development cost
- Not disclosed
- AI-written code
- Not disclosed
“実装側は今回 Claude Code、モデルは Opus 4.8 に任せました。”Verification notes: AI use, the workflow and the game's design come from the developer's Qiita article (30 Jun 2026, 21:17 JST), re-read with its Markdown source on 7 Nov 2026; it links the play address, which loaded on 7 Nov 2026. The article says Claude Code did the implementation with small fixes afterwards and gives no code share; who made the follow-up fixes is not stated. The chat AI used for the requirements is not named in this article (it lists ChatGPT, Gemini and Claude as examples of chat AIs), so no chat tool is recorded. “Opus 4.8” is quoted as the developer wrote it. The article's Markdown contains unfilled editor notes (for example whether saving works in the web version); the game's script stores progress in localStorage (observed). The Japanese interface was observed in the game's script (labels such as 弓兵, 槍兵, コイン不足); the script contains no AI service addresses. The developer describes the format as the idle defense games seen in ads; no specific game is named. The Qiita handle aonami3902_ and the GitHub Pages account aona0530 are linked through the article; team size is not stated beyond the article's “個人開発” tag. The release date is not stated. The game was not played.
Development history
The developer's Qiita article describes building the game with Claude Code from a requirements document and links the browser version.
DeveloperQiita (aonami3902_)
Game performance
Each figure measures something different — concurrent players, owners, downloads and sales are never interchangeable and are never added together. Labels show where each number comes from.
Browser (official site)
Free in the browser; the developer says it can be played on PC.
No public metrics recorded for this listing.
Not publicly available: Concurrent players (site), Monthly revenue, Gross revenue.
Sales & revenue (all platforms)
Browser game — there are no downloads to count.
Reviews & rankings
Not yet reviewed by our editors.
Not currently ranked.
Sources
| Source | Type | Published | Accessed |
|---|---|---|---|
| 要件定義書を作り込んでから Claude Code に投げたら、3D放置ゲームがほぼ一発で動いた話【実践編】 Qiita (aonami3902_) · Japanese | Devlog | Jun 30, 2026 | Nov 3, 2026 |
| Official game page (language check) aonami | Official site | Not confirmed | Nov 3, 2026 |
Get your badge
Made this game? Add a “Featured on VibeGameDB” badge to your site, GitHub README or itch.io page.
<a href="https://vibegamedb.com/en/games/coin-houchi-boei" target="_blank" rel="noopener" title="View コイン放置防衛 on VibeGameDB – the database of AI-built games">
<img src="https://vibegamedb.com/badges/featured-light.svg" width="250" height="54" alt="Featured on VibeGameDB – コイン放置防衛, an AI-built game" />
</a>Similar games
