CPC here. I really enjoyed this experience. It's a novel idea and well executed for how short a time we had to work on it. The sound effects, ambient sound, and interface all blend together to make convincing experience without drawing attention to themselves individually (there was even a point when I had to mute the audio to check if the bird tweets were coming from outside or my speakers).
I played through it a few times with different scenarios in mind and I found it worked best when I was able to fill in the dialogue for the other person. The downside is it's difficult to fill in without knowing the possible responses. I'm afraid I don't have any suggestions, and you can decide if it's even worth addressing.
If you do decide to continue working on this, I would like it if past responses influenced the tone of future options. Either that or somehow find a way to display more response choices at once.
Overall very impressed. Great job!