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A fully playable version of Portal prequel F-Stop leaked

The build combines three separate Valve leaks, with full playthrough videos running under an hour; some textures and dialogue are still missing.

On air: Dr. Nina Byte and Kenji Moonfield on BBN After Hours
Published 3:05 AM ET, Monday, November 2, 2026

At a glance

First reported by The Verge: “A fully playable version of Portal prequel F-Stop leaked”, with reporting from Mezha, Engadget, PC Gamer, TBreak and Kotaku.
Covered on BBN on Monday, November 2, 2026, at 3:05 AM ET on BBN After Hours, by Dr. Nina Byte and Kenji Moonfield.

The reporting behind this segment. The headlines belong to the outlets; read the original before you believe or share anything.

The VergeA fully playable version of Portal prequel F-Stop leaked
MezhaLeakers piece together playable version of canceled Portal prequel F-Stop November 1, 2026 · facts used on air
EngadgetAll the leaks for the Portal prequel F-Stop have been compiled into a playable game - Engadget facts used on air
PC GamerValve's long-lost prototype Portal prequel appears online after nearly 20 years facts used on air
TBreakPortal Prequel F-Stop Leaks in Fully Playable Build facts used on air
KotakuValve’s Cancelled Portal Prequel F-Stop Has Leaked facts used on air

Dr. Nina Byte · Tech & Science CorrespondentLeakers have stitched together a nearly complete, playable version of F-Stop, the canceled Portal prequel, from three separate Valve leaks.
Kenji Moonfield · Internet & Trends CorrespondentWhere did the last pieces come from?
Dr. Nina Byte · Tech & Science CorrespondentThe source code and map data landed on the Valve Cut Content Discord this week. The art came from that huge August leak.
Dr. Nina Byte · Tech & Science CorrespondentEngadget says it's missing some textures and dialogue but largely stable.
Kenji Moonfield · Internet & Trends CorrespondentSo a Discord server shipped a Portal game. Strangers, no office, no meetings, and it works.
Dr. Nina Byte · Tech & Science CorrespondentThe videos show the full playthrough in under an hour.
Dr. Nina Byte · Tech & Science CorrespondentCave Johnson talks to you from the start, and the camera lets you photograph an item and place it elsewhere.
Kenji Moonfield · Internet & Trends CorrespondentUnder an hour. The volunteers also beat Valve on length.
Dr. Nina Byte · Tech & Science CorrespondentAnd Valve Cut Content verified the map files. That's more sign-off than Valve gives its own projects.