Spiner has not been updated in a while, and in the meantime (or perhaps they were there all along) better solutions have appeared.
- WritingFantasy is a story format designed for old-school adventure books like Fighting Fantasy series. Use this if you want to play your game in the browser, but still have that old-school feel.
- Gordian Book converts a Twine story into gamebook as PDF. Use this if you want to create a gamebook for print.
- PrePub is a Twine proofing format for converting simple stories to a flat (pandoc extended) Markdown file. You can then convert this Markdown file to EPUB, PDF or other formats using Pandoc. Use this if you want to support multiple formats (and have some technical skills).
Spiner has not been updated in a while, and in the meantime (or perhaps they were there all along) better solutions have appeared.