WOW!! As someone who hates hates hates horror games, you really nailed the exact fear that I run away from. The entire interface (messages, downloads, etc) was so clever and well done, especially given that we were using Twine.
I felt very proud of myself for figuring out the code, even if that meant listening to terrifying audios. On that note, I want to congratulate you on your usage of audio / sound art to create a really terrifying backdrop to your piece.
The writing of your game was very well done, especially the religious moments, and I think with more time given you could've done a masterful job of building suspense between the casual conversations in your messages to the super creepy religious prose.
Overall, this game feels like a fantastic prototype to something that could be a 20+ minute horrifying experience. I'd love to build more of a relationship with Jimbo(?), or at least have more "lore" or a stronger understanding of who I'm supposed to be and why I've received these strange files. I think providing more context for the player and the world they're in will draw them even further into the game.