# Fully playable Portal prequel F-Stop leaks online

A fully playable version of F-Stop, Valve’s canceled Portal prequel prototype, has leaked online. The project was an experimental concept tied to Portal’s development before Portal 2. Its release gives gamers and preservationists a rare look at cut Valve history.

**Importance:** 2/5

## Sources

### Technology
- [The Verge](https://www.theverge.com/games/1024206/playable-portal-prequel-f-stop-leak) — 2026-11-01T11:19:21-05:00