Strong aesthetic, I feel the setting and its 100% clear and cohesive. I'm not familiar with switchboard operation but I get the feeling the sound design is on point for that. Simple and effective way to tell the story and it works.
I dont think there is much "gameplay" to be had here though; I decided to let the timer run out just to see what happens while I was near the end of the story, and sure enough its just a game over and you have to re-do EVERYTHING. I think when the biggest reward for the game is the story, having the user start from square 1 is a pretty big sin. Yes it's not that hard to find the right line and you do get ample time, but I could see there being more people like me who decided it wasn't worth the effort to start the whole thing over again for the ending. Checkpoints at certain points could quickly cover this gap.