Branching narratives are like Choose Your Own Adventure books. You can get 80% of the way to what Ink does with a carefully programmed static website. But this

Branching narratives are like Choose Your Own Adventure books. You can get 80% of the way to what Ink does with a carefully programmed static website. But this is an environment designed to author that, and to publish to game engines as well. The main competition is Twine, which is more focused on a self-contained deployment. Twine also got a huge update recently with its "Harlowe" theme supporting storylets - scenes that trigger from a pool or "deck" based on logic you program.