F-Stop, a cancelled 2007 Valve project conceived as a prequel to Portal, has leaked online in a fully playable form after three separate leaks were combined. The game came out of Valve's "Directed Design Experiments," a period in 2007 when the studio split into five teams to prototype original concepts, as later described by Gabe Newell. F-Stop's gameplay centred on an experimental Aperture Science camera used to manipulate perspective to solve puzzles. The project was never released and had previously only been known through documentation on sites such as the Half-Life wiki.
Originally reported 1 November 2026. Read the full story with all the details on kotaku.com
