I think that one of the thing that make this update large for
Defiant Explorer is the free roaming.
For what I understand, it's not easy to implement this in the Twine engine.
Also, there are lot of little details which change according to your origin and ethnos.
Like if you play a Ranalian, when you try to lit the fire, Selene said she take lock of "red hair". But don't mention the color if from another ethnos.
Same, if you are of Vagrant origin, you will use your dagger to sharp some sticks. But with other origins, you will use stones.
There are certainly other details like that that I have forgotten or missed.
They seem like nothing. But it require a lot of work. And without a doubt take a lot of time.
But it's one of the thing that make this game a great game.