Alt-Life
A three-minute browser life sim about the life you didn't live, from age 26 to 45, shaped by choices and chance. The developer says an AI agent did the design and implementation.
Official site alt-life-jp.netlify.app, verified Nov 3, 2026. Linked twice as the play link in the developer's 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 siteBrowserReleasedFree
Runs in a desktop or mobile browser. No download.
Browser (no download) · Mobile · Official link verified Nov 3, 2026.
About Alt-Life
Alt-Life is a short, free life simulation for phone browsers that asks what would have happened if you had chosen differently. In about three minutes you walk one alternative life from 26 to 45 through a series of choices and chance events, choosing at crossroads and then living with what happens on the way; at the end the game names the kind of person your choices made you, based on how far you strayed from the average, and lets you share the result on X or LINE. The page's text shows four starting characters with their own strengths, among them a steady salesperson, a well-connected designer, a consultant at a foreign firm and an engineer with skills but no savings, and four stats: assets, stamina, connections and options. Per the developer, there are more than 700 possible outcomes. The developer, Naoya Takamatsu, head of the Japanese company Kohomada, says that the developer gave the requirements and an AI agent did the design, implementation, ordering of illustrations, sound design and finding its own mistakes; the agent is not named. The game picks Japanese or English from the browser language. After a run, an optional screen lets you copy a memo of your result and book a conversation with the founder.
How it was built
Partially verifiedIn a Qiita article titled “AIエージェントだけでゲームを1本作ってみた話” (making a whole game with only an AI agent, 28 Sep 2026), the developer says they asked an AI agent to make a life-simulation game that could be played to the end on a phone, and that while the developer gave the requirements, the agent did the design, implementation, ordering of illustrations, sound design and finding its own mistakes; there was no illustrator, composer or QA team. Automated playtests run by the agent flagged that first-time players would leave before the first choice, which took 20 seconds, and it was cut to 10. The article does not name the agent or the model.
Next.js 15 (App Router), React 19, Tailwind and Framer Motion, statically exported and hosted on Netlify. The game logic is a pure-function engine (createGame → crossroads → travel → arriveEvent → applyChoice) with a fixed-seed random generator; result types are decided by z-score normalization, measuring how far a run strays from the average, because simple thresholds skewed the results. The developer's lessons concern verification: a scope bug made the result screen crash for every player and was found only by playing to the end in a real browser shortly before launch; a promo-video shot showed only one of three images until frames were extracted and checked; and a re-render silently kept an old video file. The page sends anonymous play events to its own /api/log endpoint (observed in the page code).
- Engine / framework
- Next.js (React)
- Languages
- TypeScript
- Team size
- Not disclosed
- Initial build time
- Not disclosed
- Development time
- Not disclosed
- Development cost
- Not disclosed
- AI-written code
- Not disclosed
“私が要件を伝え、AIエージェントが設計・実装・イラスト発注・音響設計・そして自分の間違いを見つけるところまでやりました。”Verification notes: AI use, the age range, the tech stack, the engine design and the four bugs from the developer's Qiita article of 28 Sep 2026 (author Naoya Takamatsu, signed as representative of 株式会社コホマダ), which links the play page. The “more than 700 outcomes” figure is quoted in the article as a line from the promo video. The characters, stats, the Japanese/English switch (by browser language or ?lang=), the X and LINE share buttons, the consultation screen with a booking link and the event logging were read from the play page and its code on 4 Nov 2026 (page language ja); the consultation memo is only copied to the clipboard, per the page. No calls to AI services were found in the page code. The AI agent is not named, so the tool is undisclosed. Team size and the company's location are not stated; the article says there was no illustrator, composer or QA team. No release date is stated. The game was not played.
Development history
The developer publishes an article on Qiita about making the game with only an AI agent, with a play link.
DeveloperQiita (Naoya Takamatsu)
Game performance
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Browser (official site)
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 |
|---|---|---|---|
| AIエージェントだけでゲームを1本作ってみた話——速さより「間違いに気づけるか」が全てだった Qiita (Naoya Takamatsu) · Japanese | Devlog | Sep 28, 2026 | Nov 3, 2026 |
| Alt-Life — もし、あのとき別の選択をしていたら Kohomada · Japanese | Official site | Not confirmed | Nov 3, 2026 |
| Official game page (language check) Kohomada | Official site | Not confirmed | Nov 3, 2026 |
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