Hell, that was genius!
I love the fact that you let the player chose its own intercom inputs. It confused me at first, as I was wondering how I had to say yes and no. But when I understood that I had, in fact, decided their morse-like code, I was all like "OMG this is brilliant!".
Also, the fact that there is no menu, no title screen, no UI, etc. helps so much for the immersion! You're into the game in no time at all, just after launching the exe. And because there's no reminder of the current morse-like vocabulary on the screen, you're in constant stress, fearing for a mistake and trying to remember eveything.
Now, this game has just become my favorite GMTK 2019 entry.
Please let me know if you work further on this. I followed you to make sure I don't miss anything.