Nearly 20 years after Valve canceled it, the Portal prequel F-Stop has been reconstructed into a playable build by members of the Valve Cut Content Discord community.
The project was created using leaked assets, source code and map data. The first material reportedly emerged in August 2026 as part of a leak containing approximately 12TB of Steam data, including early versions of Portal 2 and Left 4 Dead. Further code and map data later appeared through the invite-only community, enabling fans to assemble the build.
F-Stop was developed in 2007 and was set before the original Portal. Its gameplay differs from the released games: instead of creating portals, players use a camera to photograph objects and place them elsewhere in the environment to solve puzzles.
The reconstructed version remains unfinished, with missing textures and dialogue, although a large part of the campaign is playable. Footage of the project has also begun appearing on YouTube.
The game originated during Valve’s Directed Design Experiments, an initiative in which developers worked in separate teams to explore different gameplay concepts. Valve eventually chose to develop Portal 2 instead, releasing it in 2011.
Sources: Dexerto.