This game was very fun to play! Good humour, fun story, well explained gameplays, various things to do… and voice acting! Wow! This is a great take on the subject! The choice of a “story telling” approach is bold!
I read your post-mortem, and if I only give you one advice: don’t care too much about GDD. I used to do the same thing back in the days I was student and it’s not working during game jams. Try to use a more “free” approach, only drawing a game loop, writing some intentions and main ideas. Write your story if it’s a narrative game, but don’t overthink too much the gameplay ^^
Anyay, good job! :D