Valve's canceled Portal prequel F-Stop has leaked in playable form

F-Stop, Valve's canceled Portal prequel, is now playable. Leakers have pieced together a nearly complete version of the game from material in separate leaks, as Kotaku and The Verge reported this week.

According to The Verge, most of the assets came from the 12-terabyte leak that dropped this August. That haul didn't include the game's source code or map data, but those final pieces apparently surfaced in the Valve Cut Content Discord this week.

That was enough to get the thing running. Rock Paper Shotgun says what exists of F-Stop is now fully playable.

If you've never heard of it, F-Stop came out of a post-Orange Box, 2007 Valve game jam, according to PC Gamer. It stayed pretty mysterious for years, until a much deeper look came out in a semi-official capacity back in 2020.

The hook is a camera. Instead of portals, you capture an item by taking its picture, then place it somewhere else using the resulting Polaroid. Rock Paper Shotgun called it "a pretty neat concept" and compared it to Superliminal.

Some of F-Stop's dialog and elements eventually made it into Portal 2, The Verge notes, but the core mechanic sets it far apart from the mainline Portal games.

Getting your hands on the build directly seems a little shaky right now. Full playthroughs are starting to appear on YouTube, though, including one from a creator called Meme Man?, so you can at least watch the photo puzzles in action.