A major Steam leak has exposed achievement lists for dozens of upcoming and unannounced PC games, including Persona 6, Kingdom Hearts IV, Ace Combat 8 and several previously undisclosed projects.
The data appeared on achievement-tracking service Exophase after achievements that were supposed to remain private reportedly became accessible through the Steam API.
Persona 6 is among the most notable games affected by the leak. Its achievement list reportedly contains significant spoilers related to the story and gameplay mechanics, despite Atlus having revealed relatively little about the game so far.
Kingdom Hearts IV was also affected. Its leaked achievements appear to reveal several previously unannounced worlds expected to feature in the game, potentially spoiling some of Square Enix’s future announcements.
Other titles spotted in the leaked Steam data include Ace Combat 8: Wings of Theve, Deus Ex Remastered, Horizon Hunters Gathering and Judas.
The leak also revealed information related to Thief: The Dark Project Remastered, with achievement data suggesting that the remaster could feature a new campaign titled The Tarnished Mirror.
Meanwhile, Squadron 42, the single-player game set in the Star Citizen universe, also appeared in the data. Its presence has fueled speculation that the game could eventually be released on Steam, although this has not been officially confirmed.
Not every discovery appears to be legitimate. A listing initially interpreted as evidence of a possible Balatro sequel was later reported to be incorrect.
Exophase owner Mike Bendel, known online as x3sphere, suggested that the incident may have been caused by an issue on Valve’s side, with achievements that should have remained private becoming accessible through the Steam API.
The leak could prove particularly problematic for publishers, as achievement lists can reveal story events, characters, locations, bosses and gameplay mechanics long before developers are ready to announce them.
Valve has yet to publicly clarify the full circumstances surrounding the incident.
