I've been writing the story over the last few days. It's coming together as a definite horror adventure- hopefully you like gnarly imagery!
It took me a while to find a good story-boarding tool for making mind maps and story flow that suits a choose your own adventure. I've been using draw.io and I've been quite happy with it! It just has a simple interface but it's strong enough if you're just writing and organising text to then copy and paste into a game engine.
I can get back to the coding and developing very soon, just need to tie up a few loose ends in the story. Currently it's a bit too linear so it needs to have more branches and interesting alternate paths to take.