A leaked archive said to contain around 12TB of old Valve development files, dated between 2003 and 2013, has surfaced online, and fans are already combing through it for any trace of the long-cancelled Half-Life 2: Episode Three.
The leak was first flagged on Friday by Twitter/X user Gabe Follower, who said the archive included early versions of Portal 2, Left 4 Dead, and CS:GO, along with assets from the cancelled Portal prequel F-Stop, and “potentially” material tied to Episode Three.
Someone leaked 12 TB of Valve’s internal builds and game assets from 2003 to 2013. This includes early versions of Portal 2, Left 4 Dead, CS:GO, F-Stop and potentially EP3. The community is still researching everything, so the next few days might be insane… There’s a Weaponizer… pic.twitter.com/Sg7OqJjL2X
— Gabe Follower (@gabefollower) August 29, 2026
So far, the leak is thought to contain a 2009-era Portal 2 beta build alongside a model for the “Weaponizer”, a weapon previously associated (if never confirmed) with Episode Three, though here apparently repurposed as a placeholder asset within Portal 2 itself.
Elsewhere in the archive, people have identified a fully playable Left 4 Dead beta build dated June 2008, complete with an early HUD, a work-in-progress lobby screen, and cut audio, including lines originally recorded for Zoey by Alésia Glidewell before Jen Taylor replaced her in the final game.
The material reportedly comes from Valve’s old Steam2 content-delivery infrastructure, which the studio phased out in favour of SteamPipe in the early 2010s.
This differs from the cyber attack Valve disclosed earlier this month, when its European shipping partner, CEVA Logistics, was breached and hardware customers’ personal details were exposed, rather than any of Valve’s own game data. Valve hasn’t commented on this latest leak.
With 12TB to work through, it’ll likely be days before the community has any clearer picture of exactly what’s in there, Episode Three included.
We already had an inkling – if, admittedly, no specific confirmation – that Valve is working on a major new Half-Life project of some kind. After a trustworthy report in 2024 detailed datamined assets, backing up a leak from an actor likely involved, we were told the new Half-Life project, codenamed HLX, was not just in development but now “playable, end-to-end”.
What we do know for sure is Half-Life 3 was in development 2013/2014, and was set to be a procedurally-generated, replayable game that fused Left 4 Dead-inspired gameplay with scripted story moments. It was cancelled because it was built on the unfinished Source 2 engine.
