The Metal Slug team’s last-ever game — a GPS-based creature-collecting RPG for the Game Boy Advance that was designed roughly fifteen years before Pokémon GO turned location-based gaming into a global phenomenon — is finally getting a release. Publisher Happinet announced on September 9, 2026 that Navinosuke: The Yo-kai Buster will launch for Nintendo Switch and PC via Steam in 2027, with a playable demo confirmed for the Happinet booth at Tokyo Game Show 2026, which is scheduled to open on September 17 at Makuhari Messe in Chiba, Japan, according to Happinet’s September 9, 2026 announcement.

The announcement closes a 25-year chapter that began when the developer — a team of former Nazca Corporation veterans who made Metal Slug — completed the game and then watched it disappear into a drawer.

Built on GPS, Then Shelved When the GPS Unit Died

In the early 2000s, Navinosuke: The Yo-kai Buster was conceived for a Game Boy Advance GPS peripheral that Nintendo was developing but never commercially released. The game’s design logic was straightforward: players would walk to real locations, the GPS would register their position, and different yokai would appear depending on where they were standing. It was, in other words, the core mechanic of Pokémon GO — implemented on 2001-era handheld hardware, more than a decade before smartphones made GPS gaming technically and economically viable, as Automaton West first reported.

According to Akio, the Metal Slug pixel artist who designed and illustrated Navinosuke, the team understood what they were attempting. “If development had continued as originally envisioned,” Akio wrote in June 2025 when the revival was first announced, “we could have made a game that turned walking into gameplay 15 years before Pokémon GO. Of course, I’m not saying our creepy yokai could compare to Pokémon’s beloved characters and level of influence.”

When the GPS peripheral was cancelled before reaching consumers, the team reworked Navinosuke into a traditional handheld RPG — removing the location mechanic and retaining the yokai-collection combat — but the game was shelved anyway, due to circumstances the studio describes only as “undisclosed.” It was, according to Akio, the last game the Metal Slug team ever made before the unit disbanded after SNK filed for bankruptcy in 2001.

Who the Kohachi Studio Team Is

Navinosuke is being revived by Kohachi Studio, an indie developer founded by veterans of the Japanese arcade golden age — including former members of Nazca Corporation, the Osaka-based company that developed the original Metal Slug before being absorbed by SNK in October 1996. Nazca was itself founded by defectors from Irem, the arcade manufacturer behind R-Type, and its approximately 30 staff members were responsible for two of the Neo Geo’s most celebrated titles: Neo Turf Masters and Metal Slug.

The team that made Navinosuke represents a significant departure from that action-game legacy. Nazca was known for dense, hand-drawn pixel animation and frantic arcade design. Navinosuke is a turn-based RPG about folklore and creature friendship. The studio’s representative, Shinano Ishiguro, told Automaton West that getting the game to this point required years of effort — “talking to everyone he knows in the industry and almost giving up on several occasions along the way.”

Into Haunted Ancient Japan

Navinosuke: The Yo-kai Buster is set in a fictional version of ancient Japan in which the fragile equilibrium between humans and supernatural creatures has begun to collapse. The game’s protagonist is Navinosuke — a karakuri (mechanical puppet) onmyoji apprentice created by the secretive Onmyo Bureau as humanity’s last defense against a rising yo-kai threat. The twist in the narrative is structural: the soul of a modern-day human has been transported more than a thousand years into the past, and their fate has become intertwined with Navinosuke’s. The game asks whether this pairing — a mechanical exorcist from ancient Japan and an ordinary human from the present — can restore what has been lost, and what it costs them to find out, as described in Happinet’s full game overview. The emotional register is melancholy Japanese fantasy: a world where history and mythology bleed into each other, and where the supernatural is something to be negotiated with rather than defeated outright.

The design roots the creature roster in actual Japanese mythology rather than invented monsters. Recruitable creatures include the Nekomata (an aged cat that develops supernatural abilities), the Gashadokuro (a titanic skeleton said to form from the unburied dead’s grudges), and the Baku (a creature that devours nightmares). These are drawn from centuries of documented yokai tradition, lending the roster a density that genre comparisons to Pokémon understate: Pokémon are invented; these creatures come with their own cultural histories.

What the GPS Design Means for Gaming History

The design of Navinosuke is significant not only as a curiosity but as evidence that the Metal Slug team was independently working toward a design space that two major gaming movements would later validate.

The creature-collecting RPG genre in 1996 was established by Pokémon. But a yokai-specifically-themed creature collector — one that drew on Japanese folklore taxonomy rather than invented creatures — didn’t reach mainstream success until Level-5’s Yokai Watch franchise in 2013. Navinosuke predated Yokai Watch by roughly a decade.

Separately, the GPS-based location encounter mechanic — where physical movement in the real world triggers in-game events — was the core innovation when Niantic launched Pokémon GO in 2016. Navinosuke was designed around the same mechanic concept approximately fifteen years earlier, on hardware whose GPS peripheral never reached consumers, as Automaton West’s original reporting established.

The game thus represents an independently arrived-at convergence of two trends — folklore-specific creature collection and GPS-based encounter triggering — that would later prove to have enormous commercial and cultural appeal. It is the answer to a question nobody thought to ask: what would have happened if the Metal Slug team had shipped their final game on schedule?

How the Combat System Works

In the rebuilt version developed by Kohachi Studio for modern platforms, Navinosuke retains the turn-based structure of the original GBA design and expands it. Players recruit more than 200 yokai across five elemental affinities — fire, water, earth, phantom, and curse — and build parties for strategic combat, as detailed in Happinet’s features overview. The Shikigami support card system — named for the spirit-servants controlled by historical onmyoji practitioners — uses support cards to extend the strategic possibilities of each encounter.

The rebuild preserves the original pixel art from the Kohachi Studio team, redrawn and animated for modern screens, while updating the UI and adding quality-of-life features that did not exist in the GBA era — including togglable quest and objective markers to help players navigate the game’s structure without the guidance systems modern players expect.

What to Expect at TGS 2026

Navinosuke: The Yo-kai Buster will be playable for the first time at Tokyo Game Show 2026, scheduled to run from September 17 through September 21 at Makuhari Messe in Chiba, Japan — approximately 25 kilometers (16 miles) northeast of central Tokyo. Happinet will host the demo at its booth, as confirmed in the Gematsu TGS demo announcement.

TGS 2026 is itself notable as the show’s 30th anniversary edition and its first-ever five-day format, with 759 confirmed TGS 2026 exhibitors from 51 countries. For most players, the TGS demo will be the first opportunity to spend time with a game that, until September 9, 2026, had no confirmed publisher and no confirmed platform beyond Nintendo Switch.

The full release will support five languages: English, Japanese, Korean, Simplified Chinese, and Traditional Chinese. Pricing has not been announced. The game is available to wishlist on Steam now (app ID 4467420).

Frequently Asked Questions

What was the Game Boy Advance GPS peripheral, and why did it matter for Navinosuke?

Nintendo developed a GPS unit designed to connect to the Game Boy Advance as an add-on peripheral, but the device was cancelled before it reached consumers — battery drain, GPS chip size, and satellite acquisition time made it impractical for handheld hardware in 2001–2003. Navinosuke was built around this peripheral: the original design would have registered a player’s real-world GPS position and spawned different yokai depending on location. It is precisely the mechanic that made Pokémon GO a global phenomenon when Niantic launched it in 2016, enabled by the smartphone hardware infrastructure that didn’t exist in 2001. When the peripheral was cancelled, the development team reworked Navinosuke into a traditional handheld RPG — but even in its reworked form, the game was never released.

Why was Navinosuke shelved even after it was reworked without GPS?

The studio describes the circumstances as “undisclosed” — meaning the specific reason the game didn’t ship has never been publicly explained. What is known: the reworked version was completed, the GPS component was removed, and the game was still shelved. The most plausible contextual factor is the state of SNK, the publisher behind Nazca’s work: SNK filed for bankruptcy in 2001, and the team disbanded. The studio representative told Automaton West that it took years of effort and nearly reaching a breaking point multiple times before the game’s revival could be arranged.

Is Navinosuke similar to Pokémon or Yokai Watch, and how does it differ?

Navinosuke shares the core loop of creature-collection RPGs — encounter yo-kai, battle them, recruit them, build a party — that Pokémon established in 1996 and that Yokai Watch made specifically Japanese-folklore-focused in 2013. Navinosuke predates both in its concept (the GBA version was completed around 2003) and in its use of actual yokai from Japanese mythology rather than invented creatures. The key mechanical difference in the rebuilt version is the shikigami system — support cards named after the spirit-servants of historical onmyoji practitioners — which adds a layer of strategic depth to party building beyond elemental affinities alone. The GPS mechanic that would have set Navinosuke furthest apart from its genre peers was removed before the game was shelved and will not appear in the 2027 release.

What platforms is Navinosuke coming to, and when can players expect a release date?

Navinosuke: The Yo-kai Buster is confirmed for Nintendo Switch and PC via Steam in 2027. No specific release date within 2027 has been announced. No pricing has been announced. The game is available to wishlist on Steam now (app ID 4467420). A playable demo is scheduled for Tokyo Game Show 2026, which opens September 17 at Makuhari Messe in Chiba, Japan — the first opportunity for players to experience the game in any form.