Steam Leak Reveals Dozens of Unannounced Games and Their Achievements

What Happened: The Steam API Leak Explained

The leak stems from a Valve error. Achievement data that should have been private became accessible through Steam's API, meaning details for games not yet announced were suddenly readable by anyone who queried it. That included full achievement lists for upcoming titles and, in many cases, secret achievements that reveal story elements.

The result is a large batch of unreleased games having their contents exposed at once, including projects rumored to be games no one knew existed.

How the Leak Surfaced

Exophase picked up the exposed data, a site that tracks trophies and achievements across platforms. Because the private achievement data was accessible through the API, Exophase automatically cataloged it and pushed the information to a wide audience before anyone caught the error.

The site's owner addressed it publicly on ResetEra, describing it as an apparent mistake on Valve's end: games with achievements that should have stayed private were accessible through the API and got scanned as a result. Where a game had no visible name, it was logged under its Steam App ID.

Full List of Unannounced Games Leaked

The following titles were among those revealed, as cataloged by Exophase:

• Deus Ex Remastered
• Thief: The Dark Project Remastered
• Tomb Raider: Legacy of Atlantis
• Persona 6
• Kingdom Hearts 4
• Silent Hill: Townfall
• Control: Resonant
• Gears of War E-Day
• Minecraft Dungeons 2
• Judas
• Kena: Scars of Kosmora
• Stranger Than Heaven
• Valor Mortis
• Road Kings
• Stuntman: Hollywood
• Horizon Hunters Gathering
• Attack on Titan
• 4:LOOP
• WARDOGS

Several more titles appeared under placeholder names and remain unconfirmed. Based on early community investigation, these reportedly include a new Walking Dead collection, a Shrek game, a Twin Peaks title and a project tied to Dune, though none are officially verified.

The Biggest Reveals

A few entries stand out. Persona 6, long expected but never formally dated, appears in the leak. Kingdom Hearts 4 had substantial secrets uncovered, including references to a Star Wars world. Gears of War E-Day and Control: Resonant, both already known, had further details exposed through their achievement lists.

The presence of remasters such as Deus Ex and Thief: The Dark Project also points to projects that publishers had not yet announced.

Why This Leak Matters?

The concern is not only that unannounced games were revealed, but that secret achievements were too. These often describe late-game events, endings, or plot twists, so for several unreleased titles, key story moments are now public well ahead of launch. For studios, that undercuts months of planned reveals, and for players who want to go in unspoiled, the details are now difficult to avoid.

It also reminds us how much unreleased information sits behind platform APIs, and how a single configuration error can expose it. Coverage is still developing, and more titles may be identified from the leaked data.

Get These Games on Steam When They Launch

Most of these titles will release on Steam once they are officially announced. When they do, a Steam Wallet Gift Card is a simple way to add funds to your account and pick them up at launch, with the balance ready to spend the moment a game goes live. You can browse Steam Wallet options and the wider gaming range on StanShop.

FAQs about Steam Leak Games

What was revealed in the Steam leak?

A Steam API error exposed achievement data for dozens of unannounced and unreleased games, including full achievement lists and secret achievements that reveal story details. Titles such as Persona 6, Kingdom Hearts 4, and Gears of War E-Day were among those affected.

How did the Steam leak happen?

Achievement data that should have been private became accessible through Steam's API, apparently due to an error on Valve's end. The tracking site Exophase automatically cataloged the exposed data, which spread it publicly.

When did the Steam leak happen?

The leak surfaced in the early hours of 9 September 2026 and was reported across gaming outlets the same day.

Which unannounced games were leaked?

Confirmed titles include Persona 6, Kingdom Hearts 4, Silent Hill: Townfall, Deus Ex Remastered, and Gears of War E-Day, among others. Additional games appeared under placeholder names and remain unverified.

Does the leak contain spoilers?

Yes. Because secret achievements were exposed, some leaked details describe late-game events and story elements for games that have not yet been released.