Twine - Twine is an open-source tool for telling interactive, nonlinear stories.
Ink by Inkle - ink is a popular open source scripting language for branching stories, designed for writers
ChoiceScript - ChoiceScript is a simple programming language for writing multiple-choice games (MCGs) like Choice of the Dragon. Writing games with ChoiceScript is easy and fun, even for authors with no programm…
Chronicler - ChoiceScript Visual Code Editor
Spatterlight - Spatterlight is a native Cocoa application which plays most kinds of interactive fiction game files.
Quest - Quest lets you create sophisticated text-based games, without having to program.