Thanks for the interesting and detailed feedback!
Most of the issues you highlighted are indeed bugs (the anomaly spawning behind the player, mouse sensitivity, and the broken jumpscare).
As for the "build-up of fear," we are definitely thinking about it. Our main concern was that if we made a slower intro/backstory, we might lose the player's attention too early. So right now, we are trying to figure out how to make that build-up engaging enough so the player doesn't close the game before reaching the core gameplay.