Johnny Castaway for macOS

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.
Github

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.