モンキュペ
A monster-raising browser RPG: befriend and evolve 78 monsters, grow feed on your farm, clear nine dungeons and battle friends' parties by password.
Official site itamoko.itch.io, verified Nov 3, 2026. The developer's own itch.io page (itamoko), linked from the developer's Zenn article.
Where to play
Every platform this game is on. Links are checked against official sources; we never host or mirror games.
- Play free — itch.ioitch.ioReleasedFree
Plays in the browser on itch.io. No download.
Browser (no download) · Mobile · Official link verified Nov 3, 2026.
About モンキュペ
モンキュペ (Monkyupe) is a free monster-raising RPG in the browser for PC and smartphones. You befriend monsters, raise and evolve them, grow crops on a farm to feed them and take your party through dungeons and boss battles. Per the developer, there are 78 monsters with evolution lines and nine dungeons, and a password battle mode turns your party into a short code that a friend can enter to fight it as a computer-controlled team, with no server involved. The whole game is a single HTML file with no image files: all 78 monster sprites are drawn in code from generation parameters, by mirroring a randomly built half of a 16 by 16 grid, and progress is saved in the browser. The developer, itamoko, a third-year university student who says they can hardly program, writes in a Zenn article that Claude Code wrote all the code and proposed much of the technical design, and that, when asked to balance the final dungeon, it ran automatic simulations that played it 200 to 300 times per condition; the developer did the planning, the specifications in numbers, the playtesting and bug reports, and the itch.io release. In Japanese, free on itch.io.
How it was built
Partially verifiedThe developer writes: “コードを書いたのはClaude Codeで、技術的な設計もかなりの部分がClaudeの提案です。” (Claude Code wrote the code, and much of the technical design was Claude's proposal too.) The article's table of roles gives Claude Code all code implementation, technical design proposals (including the single-file, no-assets constraint), automatic balance simulations, bug investigation and fixes, and technical troubles at release; the developer did the planning and world, specifications in numbers, playtesting on real devices, bug reports and the itch.io release. The developer had used Claude Code for one week and says they could not review the code, so they judged it by asking for tests and simulation results.
- Developeritch.io AI disclosure: “AI Assisted”, covering Code, Graphics and Text. — itch.io
About one week of development. At the start, the developer and Claude Code agreed on constraints: a single index.html with all CSS and JavaScript inline, no external images, CDNs, npm packages or build tools, all images generated on canvas in code, and saves in localStorage; the distributed zip is 84 KB. Monsters are stored as generation parameters (template, palette, features, seed, stage) rather than pixel data, so adding one takes a few lines. The password battle encodes an 8-byte party (version, species and level for three slots, checksum) in Base32 without I and O, and the receiving side rebuilds stats and sprites from the same parameters. After release, the developer had all 35 browser alert and confirm dialogs replaced with in-game dialogs because on itch.io they broke full screen, showed the iframe's domain in a warning-like box and, on some mobile browsers, reloaded the page.
- Engine / framework
- None (vanilla JavaScript, single HTML file)
- Languages
- JavaScript
- Team size
- 1 (solo)Developer ReportedZenn (itamoko)
- Initial build time
- About one weekDeveloper ReportedZenn (itamoko)
- Development time
- Not disclosed
- Development cost
- Not disclosed
- AI-written code
- Not disclosed
“コードを書いたのはClaude Codeで、技術的な設計もかなりの部分がClaudeの提案です。”Verification notes: The AI claim, the division of work, the constraints and the technical details come from the developer's Zenn article published on 6 Jul 2026, re-read on 4 Nov 2026, which links the itch.io page; the counts of monsters (78) and dungeons (nine) are the developer's. The itch.io page, read the same day, gives the description in Japanese and English, status Released, genre Role Playing, the tag japanese and an AI disclosure of AI Assisted for code, graphics and text; it shows no publish date, so no release date is recorded. The game's HTML (title モンキュペ, page language ja) is a single file with no external scripts other than itch.io's loader and contains no calls to AI services or servers; the password battles are encoded and decoded in the page. Team size 1 rests on the article's “1人で作り” (made alone). The article mentions the password scheme was modelled on an old console-RPG password idea suggested by Claude; that is a technique, not borrowed content. itch.io shows no rating and no download counts. The game was not played.
Development history
The developer publishes a Zenn article on building and releasing the game with Claude Code.
DeveloperZenn (itamoko)
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.
itch.io
Free in the browser (HTML5) on PC and smartphones.
Not publicly available: itch.io rating, Gross revenue.
Reviews & rankings
Not yet reviewed by our editors.
Not currently ranked.
Sources
| Source | Type | Published | Accessed |
|---|---|---|---|
| コードが書けない大学生が、Claude Codeだけでモンスター78体のブラウザRPGを作って公開した話 Zenn (itamoko) · Japanese | Devlog | Jul 6, 2026 | Nov 3, 2026 |
| モンキュペ by itamoko itch.io · Japanese | Store page | Not confirmed | Nov 3, 2026 |
| Official game page (language check) itamoko | Official site | Not confirmed | Nov 3, 2026 |
