やみだまり
Free · play online in your browser, no download
A clingy virtual pet who lives only in your browser: she remembers what you say, sulks when ignored and is gone if you clear your data. The developer says Claude Code writes most of the code.
Official site ynihility.itch.io, verified Nov 3, 2026. Linked as the game's free itch.io page in the developer's own note posts of 27 and 29 Oct 2026.
itch.io tags include Dark and Horror; the pet's moods include obsessive attachment and sulking, and the page says these emotional expressions are fiction and not meant to make fun of real mental illness. (itch.io)
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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) · Official link verified Nov 3, 2026.
About やみだまり
やみだまり (Yamidamari) is a free virtual-pet game that runs in the browser. Yami-chan exists only in your browser: talk to her and she remembers, look after her and she grows attached, leave her alone and she sulks, and her colour, way of speaking and attitude towards you change with her mood (attached, sulking, ignoring you, happy and more). There are levels, achievements, titles, rooms to redecorate, outfits, a collection log and three mini-games, among them a runner. The page stresses that it works fully offline and sends nothing anywhere: conversations and records stay on your device, and clearing the browser's data deletes her for good, so the developer recommends a computer for keeping her long term. It notes that her emotional expressions are fiction and not meant to make fun of real mental illness. The developer, ynihility, says the game is a single HTML file of about 9,400 lines made alone, and that most of its code is written by Claude Code; Claude also played the game to capture the itch.io cover and screenshots. Free in the browser on itch.io, in Japanese, with a short English summary on the page.
How it was built
Partially verifiedIn a note post (27 Oct 2026) the developer writes: “コードの大部分は、AI（Claude Code）に書いてもらっています” (most of the code is written by AI, Claude Code). The post describes a Claude Code hook the developer built so that every time the AI edits the HTML file, a syntax check runs and any failure goes back to the AI to fix; a save-handling fix was tested this way under six start-up conditions and checked by a second AI, while the developer launches the game, checks how it plays and decides what to commit. A post of 29 Oct 2026 says Claude drove the game with Playwright from a demo save to capture the cover GIF and the 1280×720 screenshots (seven planned; eight were kept on the page); the developer uploaded them.
- Developeritch.io AI disclosure: AI Assisted, Code. — itch.io
Made alone by the developer, with most of the code written by Claude Code, per the developer. The game is a single HTML file of about 9,400 lines; a Claude Code hook runs a dependency-free syntax check (check.mjs) after every AI edit and reports failures back to the AI, and the developer publishes the hook as html-check-hook on GitHub. Saves are kept in the browser's localStorage.
- Engine / framework
- None (single HTML file, vanilla JavaScript)
- Languages
- JavaScript, HTML
- Team size
- 1 (solo)Developer Reportednote (まお / YNihilty)
- Development time
- Not disclosed
- Development cost
- Not disclosed
- AI-written code
- Not disclosed
“コードの大部分は、AI（Claude Code）に書いてもらっています。”Verification notes: AI use, the file size, the hook workflow and solo development come from the developer's note post of 27 Oct 2026 and the screenshot workflow from the post of 29 Oct 2026, both read through note's API on 6 Nov 2026; both link the itch.io page. The game's description, the AI disclosure (“AI Assisted, Code”), tags (including chat, Dark, Horror and Virtual Pet), status (Released, HTML5) and the last update (28 Oct 2026, 23:18 UTC) come from the itch.io page as saved by our researcher on 6 Nov 2026; our own re-fetch that day was rate-limited by itch.io. The page's author line links the note account and the X account YNihilty. “Talking” to the pet is local: the HTML5 build has no network calls and contacts no AI services (checked 6 Nov 2026), and the page says nothing is sent anywhere. The first publication date is not shown. No ratings were visible, and the itch.io page shows no download count.
Development history
The developer describes the Claude Code hook used to check the game's code and a save-handling fix.
Developernote (まお / YNihilty)itch.io page updated (23:18 UTC) with a new build, a cover GIF and screenshots that Claude captured by playing the game.
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.
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 |
|---|---|---|---|
| AIの書き間違いを、AI自身に気づかせる仕組みを作った note (まお / YNihilty) · Japanese | Devlog | Oct 27, 2026 | Nov 3, 2026 |
| itch.ioの紹介画像を、AIにゲームを動かして撮ってもらった note (まお / YNihilty) · Japanese | Devlog | Oct 29, 2026 | Nov 3, 2026 |
| やみだまり by ynihility itch.io · Japanese | Store page | Not confirmed | Nov 3, 2026 |
| Official game page (language check) ynihility | Official site | Not confirmed | Nov 3, 2026 |
