Snowbrush comes with the following built-in features:
Save/load system using browser local storage, with optional JSON file export/import.
Exposed game state allowing any variable to be stored and auto-saved.
Persistent timers that trigger custom actions after a set time, surviving saves/loads.
API for passage navigation, screen locking/unlocking, action delays, random numbers generation, ...
Alert and confirmation prompt functions.
Custom forms in passages with custom onSubmit handlers, with the possibility of saving any input fields to state.
Back and forward buttons for story state navigation.
Dynamic sidebar, allowing you to add custom menu items, avatars, stats with progress bars.
Pop-up passages that don't advance the main state.
Markdown support respecting Twine's custom syntax.
How to use
Open Twine 2.x, navigate to the "Twine" tab and click on "Story Formats"
Click on the button marked "+ Add"
Paste the following link (address) into the field and press "+ Add"
To use the story format in one of your stories, you will need to open your story, navigate to the "Story" tab, press the "Details" button, and then select the story format from the dropdown.