Playable build of cancelled Portal prequel F-Stop leaks online

Leakers have pieced together a nearly complete, playable version of F-Stop, Valve's cancelled Portal prequel. Most assets came from a 12-terabyte leak in August, while the missing source code and map data surfaced this week. Developed in 2007, the game uses a camera mechanic that captures objects in photos and places them elsewhere. Its full campaign runs under an hour.