I’m using Notepad++ and my favourite feature is that the line numbers are on the side so it’s super easy to find errors.
I write an outline with just a few words of “setting” info per chapter to remind myself, then a couple of choices and how they’d work out for the player (and what stats are relevant).
Then I’d cut and paste a scene from the outline into Notepad ++, and fill in the program properly (writing little bits of text very badly - or quite well, if I had an idea for a section that I didn’t want to forget), including testing. When it seems to be error-free, I do the text writing “properly”.
I’m not done writing my game yet, and I can tell my stats will need tweaking for balance - but although I looked at that while outlining, things have changed a bit along the way. So when it’s all finished and debugged, I’ll edit for statistical balance. Then, finally, re-edit all the words (sometimes by “playing” the game with Notepad++ on a tab so I can tweak it as I go along; sometimes within the program).
I’ve written “normal” novels before, and my usual novel outline is about one hand-written page. For games, it’s thousands of words. Choices are hard