Massive 12TB Steam data leak unearths lost Half-Life and Portal assets

The leak provides a rare look into the cutting-room floor of gaming history, featuring content from Half-Life 2: Episode 3 and a prototype of the Portal-universe game F-Stop. Players and data miners are currently combing through the files, which also house early iterations of major third-party titles like Mirror’s Edge, Batman: Arkham Asylum, and Dragon Age: Origins.

Valve’s own catalog has yielded the most significant discoveries so far. Beyond the long-rumored Episode 3 assets, sleuths have recovered deleted dialogue that reframes the lore of the Companion Cubes, alongside alternative sequences for GLaDOS. These files offer a candid look at the iterative process behind modern classics, though the sheer scale of the 12TB dump suggests that more secrets are likely to emerge as the community continues its deep dive into the archives.