Celtx is still there, but it'a no longer available as downloadable software. It's all online and collaborative, or something like that, and I just don't do that sort of thing. I like to have software I can download and use whenever I want, and then be able to save it and keep it private. LOL. 

I prefer to just type away in any kind of acceptable word processor, but for my game I wanted to be able to account for a lot of true/false situations and dialogue branches. So I went to check out several adventure game engines, but pretty much all of them assumed I had artwork to work with. Since I do not, I eventually settled for draw.io since an adventure game without visual elements is basically a flowchart (please, no one correct me yet, I'm too far in to move to more effective software at the moment). 

I like that it's cloud-based, so I don't have to worry about having a physical copy present at all time and I can do some quick writing at work when no one is looking. Also, I use a simple notepad app on my phone for sudden ideas that need to be jotted down quick.

I should have a better look at Twine, that you mentioned up there. Looks like it's exactly what I was first looking for, but I'm not looking forward to finding out I should rebuild my flowchart-mess in it. Damnit.