What can I say... If it's not the winner of the jam, it's easily in the top 10.
When everything is polished, from the animation of the text appearing to the polished sound effects, not to mention the physics of the notebook and the tracks left in the snow (which are also useful for gameplay!
It's perhaps a tad too slow burn for my taste, especially if, like me, you miss a num once in every five times, but on the other hand, the build-up of tension wouldn't work without this lapse of time.
I don't know if I understood the whole story, but the emotions are there.
My only slight regret is that I can see there are more elements to discover, with the Morse code numbers and indecipherable calls, but you're too caught up in the atmosphere to want to spoil it by leaving the game to take screenshots.
In short, well done!