I tried using Final Draft, but I don't think it works very well for games with multiple dialog options(like Mass Effect), unless I'm missing something?

I find the easy formatting in One Note much more effective.

You'll need some sort of exporter/converter to get it into a format the engine uses.  You don't say what engine you're using for your game, that is the most important thing you left out I feel.

Armantium, are you just asking about what script format to use (how to layout dialog with branching choices)? You're not asking how to code it, are you? (I assume you're just asking the thing several people have asked before.)

7 hours ago, Tom Sloper said:

Armantium, are you just asking about what script format to use (how to layout dialog with branching choices)? You're not asking how to code it, are you? (I assume you're just asking the thing several people have asked before.)

Of course, just the script format. Final Draft has the alt dialog option, but this is useless as  they are hidden and you have to click through them, so the alternate dialog options are not visible when the file is saved as pdf.

You're fine using One Note. 

For a project I'm working on right now, we were writing all of our quests in Twine.  It worked pretty well, except that there wasn't an easy way to get the dialogue into the code. Now one the programmers made a custom tool for us that does it all, but for writing out the story and dialogue and being able to read through and visualize it, Twine was pretty damn good.