I liked the idea with the dust storms and the windmill. It fits the horror theme well, but I don't think it fits the isolation theme.
I learned more about the lore from the description than from the game itself. Because there is no narrative in the game, the player has to perform random actions that have little basis in the story. As long as I understand what's going on and have a strong goal, I won't close the game.
The hero gets tired of doing nothing for only 1 min. Think of other reasons to direct the player to a specific place or to do a specific action. For example, the phrase "I'm scared, I want to go back to the bunker" would eliminate this ridiculous situation.
Level design should make an intuitive walkthrough. It is very easy to get lost in the fog and not very interesting to walk knowing that almost all the space is occupied by emptiness. In such places you need some landmarks, such as connected flags, a row of bushes or footprints of the main character showing the way from the bunker to the windmill and back.
Readability always comes first for the font. I couldn't read the note. Sacrifice style and make the font standard if you're not sure if the player can read your text. I'm not saying about overall 3d style here since it's a jam game and getting correct 3d models could be really tough task.
Still think the concept is nice and you can make more of it. Good luck.