Cancelled Portal Prequel F-Stop Becomes Playable After Mass Leak

Valve's long-lost Portal prequel, F-Stop, has been resurrected as a playable game after a series of major leaks. According to Kotaku, the project, which was scrapped in 2007, is now essentially complete thanks to the efforts of online communities piecing together stolen data.

The game was a prototype where players used a special camera to photograph objects, making them vanish and then reappear elsewhere to solve puzzles. This core mechanic was reportedly part of Valve's internal 'Directed Design Experiments' led by Gabe Newell.

Rock Paper Shotgun reports that the final build was assembled from three separate leaks. A massive 13-terabyte Steam data dump in August provided most of the game's assets, but lacked crucial source code and map files. Those final pieces were leaked through a Discord server in the last 48 hours, per Kotaku.

Moderators from the Valve Cut Content team state the map data was initially offered for $1,000 before being released for free. The community has since verified the files and compiled them into a working game.

Those who have played it report the build is about 99 percent complete, with only minor assets or dialogue missing. Elements from F-Stop were later reworked into Portal 2 after the original project was cancelled due to poor playtester reception, despite Newell's personal fondness for it.