Inform is one of those tools, like Game Maker and Unity, which unlocks new creativity. It’s a programming system for creating text adventures in which you can write your stories using something resembling natural language. It’s more complicated than Twine, but also consequently more powerful. It is, basically, good enough that it makes you want to write interactive fiction, even if you’ve never considered that before.
It’s exciting then that a new version has been released, “three years in the making”, which expands the languages handling of procedural storytelling.