mindtricks

Johnny Castaway for macOS

Johnny Castaway on his island

The classic 1992 Sierra story screensaver, recreated for macOS.

GitHub

Overview

A native Swift recreation of Screen Antics: Johnny Castaway — the classic 1992 Sierra On-Line / Dynamix screensaver — for modern macOS. Johnny lives on his tiny desert island, builds his raft over an 11-day story arc, fishes, gets visited by mermaids, and generally never quite escapes.

You must supply the original game files. The artwork and animation scripts are still copyrighted by Sierra/Dynamix and are not included. You provide two resource files — RESOURCE.MAP and RESOURCE.001 — from an original copy of the screensaver (they’re inside the 2005 re-release installer; the README walks through extracting them). Launch the app once, drop them in, and the screensaver is provisioned too.

Features

  • From-scratch Swift port of the reverse-engineered Dynamix engine — all 41 TTM animation scripts play to completion, with the ADS scene scheduler, walking, and the full 11-day story progression
  • The original 640×480 pixel art, crisply scaled on Retina displays
  • Ships as both a .saver screensaver bundle (Sonoma+ lifecycle handled) and a windowed player app with debug keys — pause, frame-step, 0.25×–50× speed, day skip, date/time override for holidays and night scenes
  • Sound playback when the original WAV samples are present
  • No Sierra assets bundled — you supply RESOURCE.MAP / RESOURCE.001 from an original copy (they’re inside the 2005 re-release installer); the app imports them on first launch and provisions the screensaver too
  • Byte-identical resource decoding verified against the reference C engine; story choreography locked by invariant tests and million-tick soak runs

Download

Requires macOS 14 or later. Signed and notarized.

App + screensaver (recommended):

brew install --cask d4rkwyng/tap/johnny-castaway

Screensaver only:

brew install --cask d4rkwyng/tap/johnny-castaway-saver

Prefer a direct download? Grab the notarized build from Releases. Either way, launch the app once and drop in your RESOURCE.MAP / RESOURCE.001 files (see above) — it provisions the screensaver for you.

Media

Johnny’s 11-day story arc — day 1 washed ashore, fishing by day 3, raft nearly done by day 9 — plus the holiday and night scenes the original hid for whoever left their PC on at the right time.


Release Notes

  • 0.2.5 (11 June 2026)
    • Welcome screen for the first-run resource import
  • 0.2.2–0.2.4 (11 June 2026)
    • Saver audio muted when running as the Sonoma wallpaper companion
    • Engine stops when off screen; drag-and-drop first-run import
    • Combined app+saver release zip; silent-saver fix
  • 0.2.0–0.2.1 (10 June 2026)
    • Developer ID signed + notarized releases, Homebrew tap
    • About panel, version stamped from the git tag
    • Story choreography invariant tests; playback speed ladder (0.25×–50×)
  • 0.1.0 (10 June 2026)
    • First release: complete engine — resource layer (RLE + LZW, byte-identical vs. the reference), TTM interpreter, ADS scheduler, island/walking/story, sound, .saver bundle

Credits

Stands on the shoulders of the reverse-engineering community: jc_reborn (primary reference, GPL-3 — inherited license), JCOS, castaway, and Aerial for the macOS saver lifecycle lore. Original game © 1992–1993 Sierra On-Line / Dynamix — no original assets included; not affiliated with Sierra, Dynamix, or Activision.

Graph View

Backlinks