Sunday, November 1, 2026

Get the briefing
Tech

A fully playable version of Portal prequel F-Stop leaked

Leakers have pieced together a playable version of the canceled Portal prequel F-Stop. Most of the assets came from the massive 12-terabyte leak that dropped this August. That didn't include the game's source code or map data, but those final pieces apparently hit the Valve Cut Content Discord this week, allowing a nearly complete version to be pieced together. Some dialog and elements of F-Stop eventually found…

Key points

  • A playable version of Valve's canceled Portal prequel F-Stop has been assembled by leakers.
  • The build combines assets from August's 12-terabyte leak with source code and map data posted this week.
  • F-Stop uses a camera mechanic and its full campaign runs under an hour.

Leakers have assembled a playable version of F-Stop, a canceled prequel to Portal. Most of the game's assets came from the 12-terabyte leak released in August, according to The Verge. That leak did not include the source code or map data.

Those remaining pieces were reportedly posted to the Valve Cut Content Discord this week, which allowed a nearly complete version of the game to be put together.

How the game plays

F-Stop differs sharply from the mainline Portal games. It is built around a camera mechanic in which the player captures an item by photographing it and then places it elsewhere using the resulting Polaroid-like photos. Some dialogue and elements from F-Stop later appeared in Portal 2.

The game is short. Videos showing its full campaign all run under an hour.

Origins at Valve

F-Stop was developed as part of the Directed Design Experiments, a three-month period in 2007 when Valve split into five teams to build new video game experiments.

More in Tech

The 1BlockNews briefing

The day's most important stories, in your inbox every morning. Free.