Oh wow that's really good. And you can do that right after you've finished the mission for the first time right?
I'm tempted to play through in one go and see how the story unfolds with my first time with everything, but then again sometimes in these games you make one decision which has some ridiculous random consequence that you didn't see coming. If there's any of those moments I'll probably want to undo them straight away
Yep once the mission is finished you can redo it if you want. i finished it 1 time through without changing anything, but you could finish a scene and realize you should have made another change and redo it before moving onto the rest of the game. There were really only about 3 places I would have liked to have made the opposite decision but I didn't. Most of the consequences are pretty easy to see coming as well.
I was on my way to having every good ending till the last mission where I made a couple mistakes, but I corrected it after finishing.