Monday, 2 November 2026

Valve’s cancelled Portal prequel F-Stop leaks as a playable build

Leakers have joined three separate Valve leaks into a nearly complete, playable version of F-Stop, the camera-puzzle Portal prequel scrapped in 2007.

Key points

  • F-Stop, a Portal prequel Valve cancelled in 2007, now exists as a playable fan-assembled build.
  • The build joins assets from August's Steam leak with source and map files from this week.
  • Valve has not commented, and leaked builds can carry malware.

A playable version of F-Stop, the Portal prequel Valve cancelled in 2007, has leaked online. Players who have tried it say the campaign runs under an hour and is close to complete, with a few missing assets and voice lines.

The game was never released and Valve has not said anything about the leak. This is an unofficial build assembled by fans and leakers, so it is not on Steam and Valve has not endorsed it.

F-Stop came out of the “Directed Design Experiments”, a three-month stretch in 2007 when Valve split into five teams to prototype new ideas. Its hook was a camera: you photographed an object, then placed it somewhere else using the resulting picture. Kotaku’s write-up says Gabe Newell liked the idea but playtesters did not. The project was dropped, though some of its lines, characters and ideas resurfaced in Portal 2.

Three leaks, one game

Most of the assets came from the roughly 12 to 13 terabyte Steam depot leak in late August, which covered builds from 2003 to 2013. That dump held no source code or map source data for F-Stop. That report says those two pieces appeared over the past 48 hours on the Discord server of the Valve Cut Content project, whose moderators say the person who held the map files first asked for $1,000 before handing them over free.

The Valve Cut Content team says it checked that the map files are genuine, and the community then merged everything into one build. Outlets differ on the size of the August leak, with figures of 12 and 13 terabytes both in circulation.

Treat any download with care. Leaked builds shared on Discord and file hosts are a common way to spread malware, and the files are Valve’s property. If you want the idea in a finished game, Portal is on Steam.

Valve has not commented on whether it will take any action over the leak.

Noaman Rasheed

Noaman covers gaming and streaming for Tech Prolonged: consoles, PC and mobile platforms, game services and streaming apps, and what they cost in Pakistan.