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Interpreters and File Formats

An IF story file is usually not a standalone app. It is a portable game file that runs inside an interpreter. Think of the story file as the cartridge and the interpreter as the console, except the console is made of standards, late-night compiler lore, and noble stubbornness.

Common story formats

  • Z-code: Often .z3, .z5, or .z8. Classic Infocom-style format.
  • Glulx: Often .ulx or .gblorb. A more modern VM for larger parser games.
  • TADS: Often .gam or .t3.
  • Hugo, Alan, ADRIFT, Magnetic Scrolls, Level 9, and others: Less common, but still part of the wider archive.
  • HTML: Common for Twine, some choice-based works, and web-native releases.

Browser play

Parchment is a web interpreter that can run several major IF formats in the browser. Many IFDB play links and author sites use browser interpreters so players can start without installing anything.

Browser play is ideal for:

  • First-time players.
  • Quick sampling.
  • Linking from RetroRealm pages.
  • TerpVault embedded play views.

Local interpreters

Good local options include:

  • Gargoyle for Windows, macOS, and Linux users who want broad format support and nice typography.
  • Lectrote for a simple cross-platform desktop app built around web IF interpreters.
  • Spatterlight for macOS users who want a native app and broad legacy format support.
  • Frotz for Z-machine works, especially on iPhone and iPad.
  • Fabularium for Android users who want mobile play and multiple formats.

Which should I recommend on RetroRealm?

For a beginner-friendly IF page, recommend this order:

  1. Play in browser when TerpVault/IFDB offers it.
  2. Gargoyle for general desktop use.
  3. Spatterlight for macOS users who prefer native Mac software.
  4. Frotz or Fabularium for mobile.

TerpVault metadata notes

TerpVault should track file format, interpreter recommendation, IFID when available, source URL, rights/permission status, and whether browser play is enabled. That lets RetroRealm avoid the old problem of “here is a mysterious file; good luck, traveler.”