Storyspace is described as 'software program for creating, editing, and reading hypertext fiction. It can also be used for writing and organizing fiction and non-fiction intended for print' and is an app in the News & Books category. There are four alternatives to Storyspace for a variety of platforms, including Windows, Linux, Mac, Online / Web-based and Self-Hosted solutions. The best alternative is Inform, which is free. Other great apps like Storyspace are AXMA Story Maker (Freemium), InquisitorIF (Free, Open Source) and ADLENGINE (Free Personal).
Inform is a design system for interactive fiction based on natural language. It is a radical reinvention of the way interactive fiction is designed, guided by contemporary work in semantics and by the practical experience of some of the world's best-known writers of IF.