Valve's long-lost prototype Portal prequel appears online after nearly 20 years

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F-STOP (Aperture) MAP LEAK - FULL CAMPAIGN + EXTRA MAPS - YouTube F-STOP (Aperture) MAP LEAK - FULL CAMPAIGN + EXTRA MAPS - YouTube
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As reported by Kotaku, a near-mythical canceled Valve game called F-Stop has been reconstructed from material contained in separate leaks. Direct access to the build seems a little shaky at the moment, but full playthroughs of the game, like this one by Meme Man? on YouTube, are starting to pop up online.

Most of F-Stop's assets came out in this August's Steam "teraleak," but the final pieces⁠—F-Stop's source code and mapsrc data⁠—were only just acquired by the Valve Cut Content Team Discord, which appears to have gone private amid all the newfound attention over F-Stop. With the Discord currently invite-only, you gotta know a guy (or know a guy who knows a guy) to play it yourself.

The Half-Life Wiki has the skinny on F-Stop's origins in the "Directed Design Experiments." Following the megahit launch of the Orange Box in 2007, Gabe Newell effectively shut Valve down for a three-month game jam that produced five prototypes, F-Stop among them.

It applied Team Fortress 2's cel-shaded art style to a vision of Aperture Science in its prime, all mid-century wood-paneled office optimism. F-Stop's central mechanic was a camera that could capture objects in the world, then place them elsewhere to solve puzzles. The excellent 2023 game Viewfinder would apply a similar concept to a full commercial release.

But while loved internally at Valve, F-Stop's playtests were apparently more tepid. The game was shelved, though elements of its worldbuilding would appear in Portal 2 and Aperture Desk Job. It's fun to recognize some of these early ideas in the F-Stop longplays: From the jump, we get a version of Cave Johnson (sadly sans-J.K. Simmons in prototype) talking to the player, as well as the first instance of Aperture Personality Cores as companions in the puzzling.

Given F-Stop's "road not taken" nature, particularly compared to the megathit Left 4 Dead and Portal 2 that would follow, I don't really mourn the fact that we never got to play its final version. It is, however, extremely cool that the prototype game is now preserved for posterity.

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Ted Litchfield
Associate Editor

Ted has been thinking about PC games and bothering anyone who would listen with his thoughts on them ever since he booted up his sister's copy of Neverwinter Nights on the family computer. He is obsessed with all things CRPG and CRPG-adjacent, but has also covered esports, modding, and rare game collecting. When he's not playing or writing about games, you can find Ted lifting weights on his back porch. You can follow Ted on Bluesky.

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