Thank you for the kind words! For us the key to getting a narrative game done in this time is really nailing down the scope of the story before you begin, and getting at least a draft of the whole story in as early as you can. In this case we are using some tools that we've developed from previous games (to handle narrative state, cameras, fade in/out, etc), and using that to throw the game together end to end as fast as we can.
I think we had the full story in place with placeholder scenes by Day 3 for this jam, and then we could spend the rest of the time editing and polishing the dialogue, building out the scenes, etc.
For Godot, I highly recommend Nathan Hoad's Dialogue Manager plugin, it's very flexible but gives you a lot of power to easily write branching dialogue, hook into state and events, etc.
Thanks again for playing!