Yuji Horii says he made a mystery game with AI in about 30 minutes

Yuji Horii, the designer of Dragon Quest, posted on X on 11 October 2026 at 10:01 UTC that he had made a game with AI. The post is in Japanese. This is our translation:

Long ago, when I made The Portopia Serial Murder Case on a PC, I thought up the story, drew the pictures and wrote the program myself. I made the game alone. And now, if you use AI, even if you cannot draw and even if you cannot program, you can make a fairly decent game alone, just by giving instructions to the AI. I am honestly astonished. By the way, the game below took only about 30 minutes to make. Oh, and do not press the boost button.

The link under the post is a Claude artifact. He does not name a Claude model. When that URL was opened on 12 October, a plain fetch returned the artifact shell and no game, and a browser render came back as a page not found. The frame host for the page answered 404. What follows about the game is from outlets that described it, not from a playthrough here.

When the post was read through the X API on 12 October, it showed 1,442,218 impressions, 15,031 likes, 3,822 reposts, 582 quotes, 189 replies and 5,110 bookmarks. The short text in the timeline stops before the 30 minutes and the warning about the boost button. The full note on the post has both, plus the artifact link. Horii does not say what the boost button does.

What Famitsu says the game is

Famitsu’s article, timestamped 19:41 on 11 October, gives the title as 『取調室の小宮』. Inven Global’s English article, by Seungjin Kang, also 11 October, renders that as “Komiya in the Interrogation Room.” Both say it is free in the browser.

Famitsu’s account of the play, which Inven’s matches: you are a police officer interrogating Komiya, 72, a former locksmith and the suspect in a pawn-shop vault burglary. He sometimes lies. You put evidence against the statements that do not line up. He has two meters, agitation and resistance. If resistance reaches 100 he goes silent, so you have to keep that in check while you push the case. The clear screen’s rating depends on how many lies you exposed. Famitsu attributes the “only about 30 minutes” to Horii, and closes by suggesting readers try it if they are curious how a game made that fast actually plays.

Inven adds two pieces of Portopia context. It says Enix published The Portopia Serial Murder Case, designed by Horii, in 1983. It also says that in April 2023 Square Enix shipped a free Steam tech preview, “SQUARE ENIX AI Tech Preview: THE PORTOPIA SERIAL MURDER CASE,” which took free-text input, and that low polish and ethical limits kept it from meeting expectations. That 2023 release is a different project from the artifact Horii posted this week. His post does not mention it.

The half hour, and the judgment that the result is “a fairly decent game,” are his. Famitsu and Inven report the post and describe the game. They do not publish a count of how players split on it.