Yuji Horii Says He Made a Mystery Game With AI in About 30 Minutes

Yuji Horii, the creator of Dragon Quest, released a new browser-playable mystery game on 2026年10月11日, writing in a post on his X account that he made it by giving instructions to an AI and that production took about 30 minutes. The game, titled 取調室の小宮 (Interrogation Room Komiya), is published as a public artifact on claude.ai.

In the post, Horii recalled that when he made The Portopia Serial Murder Case on PC, he devised the story, drew the artwork, and handled the programming entirely by himself. Now, he wrote, AI lets even someone who cannot draw or program make a decent game alone simply by giving the AI instructions, a shift he described as genuinely astonishing.

“The production time for the game below was just about 30 minutes,” Horii wrote. He closed the post by telling readers not to press the boost button.

Inside the Interrogation Room

The game presents the player as an interrogator facing an elderly suspect named Komiya, shown seated at an interrogation-room desk with his hands clasped. The screen is styled as an interrogation-room recording, marked REC, with an on-screen clock reading 21:00.

Two numeric parameters describe the suspect’s state: 動揺 (agitation), displayed at 10, and 反発 (resistance), displayed at 15. Play is bounded by a counter showing 20 moves remaining, and the interface text explains that each question the player selects reduces the remaining time allowance.

Six lines of questioning are offered. They ask where Komiya was just after midnight that morning; what his relationship is with the owner of the Mitsuboshi-dō shop; whether his past as a locksmith means he can open a safe; whether he recognizes the missing “Sansui-zu” hanging scroll; how he is getting by financially; and whether he will talk about his late wife. Five of the topics were tagged “not yet heard” in the viewed state, while the question about his wife was marked “no lead.”

A separate option labeled 決め手, or decisive move, becomes usable once the player has broken down four of Komiya’s lies; its counter read zero in the viewed state. The interface also carries the label 矛盾 (contradiction), with rows of ellipsis standing in for the suspect’s responses beneath it.

First-Day Counters

Counters displayed on the post on 2026年10月12日, showed 1.9 million views, 16,000 likes, about 4,200 reposts, 228 replies, and roughly 5,700 bookmarks. The linked artifact card on the post lists the game as last edited at 10:01 AM on 2026年10月11日.

Horii also returned to the boost-button warning in a follow-up post, clarifying its scope. “It seems the boost button only appears on my page,” he wrote. Counters on the follow-up showed about 171,000 views and 565 likes.

Recent Posts From Horii

Horii’s X profile gives his bio as 人生はロールプレイング — “life is role-playing” — and lists 274.2K followers on the account.

On 2026年9月19日, he posted about the heavy turnout at the public days of a game show, noting that he was able to meet many people and that The Portopia Serial Murder Case had demo stations at the event.

On 2026年9月27日, the anniversary of Dragon Quest V, Horii wrote that he devised the game’s marriage event because he wanted players to agonize seriously over a choice even though it was a game. He added that the monster-companion system also began with Dragon Quest V and was carried on into the Monsters series.

On 2026年10月3日, he posted that a reprint had been confirmed for his book 『堀井雄二のドラゴンクエストのつくりかた』 (Yuji Horii’s How to Make Dragon Quest), thanking readers and describing parts of it as fairly specialized material that takes some effort to read. In the same post, he wrote that he had played Torneko to the 99th floor and obtained the final scroll, adding that it had been tough.

On 2026年10月6日, Horii posted about a visit to Rebe, a village on Miyako Island that he said was handmade by a devoted Dragon Quest III player and was in its 19th year. He described a Full Moon event there as a night when, he wrote, everyone taking part could feel like the protagonist of their own life.