
F-Stop: The Lost Portal Prequel Emerges as a Playable Prototype
A fully playable build of F-Stop, Valve's cancelled 2007 prequel to Portal, has been reconstructed by fans using assets from multiple leaks. The game, which featured a unique camera-based puzzle mechanic, was scrapped after poor playtests but contributed elements to Portal 2. While the build is reported to be 99% complete, it lacks official release status and some polish.
