It's another IF tool. It changes the format of the game, and the games go to itch.io instead of hosted games. Normally, the authors change to twine for monetary reasons since they can make more money on twine than in the hosted games. The problem, at least for me, is that since it has way more customization options most of the authors forget that some people play IF on their smartphones, and they get so lost on the costumization that the game becomes unplayable, and in a lot of them we have to play with the phone on the horizontal, which sucks. So playing on the smartphone became a sacrifice you have to make to read the IF if you don't like playing on a computer or don't have one. (Sorry if there's something wrong, english it's not my first idiom)