Sunday, August 27, 2017

System's Twilight emulator packages

A couple of weeks ago I promised to set up emulator packages to play System's Twilight on modern machines. These are now ready!
These packages are based on Mini vMac, an open-source classic Mac emulator. Special thanks to David Pfaltzgraff-Carlson, who set up Cliff Johnson's puzzle games using Mini vMac in this manner. I just copied his package configuration.
(Yes, these packages include an unlicensed Mac ROM. The ghost of Steve Jobs can come yell at me about it.)

Some notes on play:
When your character (the red shape) is on the screen, you're either clicking through dialogue or moving around. Click left or right on your platform to move; click on nearby platforms to jump. The cursor will indicate places you can move to.
You can go to the game map (under the Game menu) at any time. This will show you all completed and in-progress levels. You can revisit a completed level to replay its dialogue (but not its puzzles).
The You menu is your inventory.
To quit, close the game (File / Quit and Save) and then shut down the emulator (Special / Shut Down). Don't just kill the emulator, or you may corrupt the Mac disk. Yes, this was a real problem in the old days.
Your game is saved on the disk images (disk1.dsk and disk2.dsk) inside the emulator package. That is to say, your save files are not kept in your real home Documents or Library folder; if you uninstall the package, your save game is gone. This is bad form on modern OSes (and is the reason the apps aren't developer-signed!). But that's the way Mini vMac works. Sorry.


  1. Thanks for putting this together, it was a fun blast from the past going through your puzzles again.

    I will note that on the version I used (Mac OS X, Intel chipset) the provided package does not appear to grant the user the permissions to write files on either disk1.dsk or disk2.dsk. I got around this by opening a blank disk image available as "" from the Mini vMac website, but thought I would note that this might be necessary in case someone else runs into the issue.

    1. Update: I think the issue I mentioned had something to do with the System's Twilight app being in the 'Downloads' folder, after I moved it the issue vanished and now I can't reproduce what happened the first time.

    2. I can't think of any reason for this to happen unless you place the app on a read-only volume. That's legal for most apps -- this one does violate MacOS conventions by writing to files inside the package. But I'm not sure why the Downloads directory would be read-only.

      I'll try repackaging it with more generous file permissions.

  2. This is fantastic. System's Twilight must have been one of the first dozen games I played on my Mac. It occurs to me that I never got past the first few puzzles - looking forward to picking up where I left off!

  3. This is simply awesome! I was finally able to recommend my all-time favorite game to my internet friends. It's a whole new experience seeing them solving puzzles together over Discord screen share.

  4. Sadly, this doesn't appear to work any longer on the latest OSX

  5. That is true.

    The emulator is Mini vMac ( It's been updated but I haven't looked at repackaging the game. Last time I looked, there were annoying configuration issues that made it difficult to ship the game as a signed Mac package.

    You should be able to set up the emulator yourself, though.