My new choice-based IF system Squiffy now has a downloadable version of the editor, and it runs on Windows, OS X and Linux.
You can download it at textadventures.co.uk/squiffy - you can also access the web-based version from there (and you can still use the command-line version via npm if you’re so inclined).
I’ll update the docs and write a proper announcement blog post in the next day or two. If anything’s broken please let me know!