Dragon Quest creator Yuji Horii says he made a detective game with Claude in 30 minutes

The creator of Dragon Quest has made a new game in half an hour. Yuji Horii shared a free detective game on X on October 11, saying it took “only about 30 minutes” and that AI now lets one person build a “pretty decent game” without drawing or programming.

The game, Interrogation Room Komiya (取調室の小宮), runs in a web browser as a Claude artifact, the shareable mini-apps Anthropic’s chatbot builds on request. Horii’s post says only “AI”, and he hasn’t said which model he used or how many prompts it took. By October 13 it had nearly 3 million views and more than 20,000 likes, and gaming sites in Japan and beyond had picked the game up.

Twenty moves to crack a 72-year-old

You play a detective questioning Komiya, a 72-year-old former locksmith (the same age as Horii) held over a pawnshop break-in in which a hanging scroll vanished from the safe. You have from 9pm until his lawyer arrives at 11pm: 20 moves, and every question eats into the clock.

Komiya lies. Asked where he was that night, he says he was asleep at home: “I was in bed by ten. Old folks turn in early.” To catch him out, you play one of five exhibits against the statement it contradicts, from a camera still of a small old man with a walking stick at the shop’s back door to a home-made lock pick stamped with a tiny “Ko” and an unpaid hospital bill. Two meters track how rattled and how defiant he is: pressing him raises both, tea calms him and silence slowly unnerves him. Push his defiance to 100 and he stops talking.

Break four lies and you can ask the decisive question. A confession earns an S, A or B grade and a short, sad explanation we won’t spoil. It’s in Japanese only and works on a phone or a computer.

“Just by telling the AI what to do”

Horii compared the game with how he worked four decades ago:

その昔、PCで『ポートピア連続殺人事件』を作った時は、自分で物語を考え、絵も描いて、プログラムもして、ひとりでゲームを作りました。そして今、ＡＩを使えば、絵を描けなくても、プログラムしなくても、ＡＩに指図するだけで、ひとりで、そこそこのゲームを作れてしまいます。ホントびっくりです。ちなみに下のゲームの制作時間は、ほんの30分ほどでしたよ。あ、ブーストするボタンは押さないように。

claude.ai/artifact/HgsUQ…

— 堀井雄二 (@YujiHorii) October 11, 2026

English translation:

Long ago, when I made The Portopia Serial Murder Case on a PC, I came up with the story, drew the pictures and did the programming myself, and made the game on my own. Now, with AI, even if you can’t draw or program, you can make a pretty decent game on your own just by telling the AI what to do. It’s honestly astonishing.

Yuji Horii, on X

Portopia, released by Enix in 1983, is a detective adventure in which you question suspects, and Metal Gear creator Hideo Kojima has named it as one of the games that drew him into the industry. Komiya has no chatbot inside: every line is written in advance, and you pick from menus.

An old idea, made in half an hour

Horii has been heading this way for a while. In April 2023, Square Enix released a free “AI Tech Preview” of Portopia on Steam that let players type their own questions; Steam reviews still rate it “Very Negative”. At the G-Star show in Busan, South Korea, in November 2025, Horii said he used ChatGPT and would love a whodunnit solved by chatting with AI characters, Famitsu reported. Asked whether he wanted that in his games, he said “yes”.

Portopia itself is coming back. Next: The Portopia Serial Murder Case, a remake with five new investigations made under Horii’s executive direction, is due in 2027 for Switch 2, Switch and PC.

Astonishing, or a warning?

Not everyone is impressed. Many readers commenting on Nintendo Life’s report of the game were scathing, and it arrived a day before Bloomberg reported that Epic Games had told its Disney game team to stop writing code by hand and let Claude do it.

Ian Dean, digital arts editor at Creative Bloq, wrote that half an hour buys a small mystery, not a commercial release, and that the craft still came from the designer:

He knows how to pace a reveal, what makes a game satisfying, what to leave out, and what to develop further, and none of that came from the AI.

Ian Dean, Creative Bloq

Horii’s game joins a run of hits made with AI coding tools, from the GeoSports trivia game a million people played to a GTA clone set in Taipei and Claude’s one-prompt Pokémon Red.

Why it matters

Horii is one of the most influential game designers alive, so his verdict that AI can turn plain instructions into a decent game in half an hour carries more weight than a start-up’s demo. Komiya also shows where the value still lies: the code took minutes, but the lies, the clues and the payoff come from the man who wrote Portopia.

Sources: Yuji Horii on X; Interrogation Room Komiya; Famitsu (G-Star 2025 talk); Square Enix AI Tech Preview on Steam; Next: The Portopia Serial Murder Case on Steam; Creative Bloq.