This game is a fun one, the atmosphere is really good, so are the graphics, the game play is also good, but I have some ideas to improve it [this is if you make a post jam version]
1. Make the controls on the mouse, the keyboard controls are weird for a game like this, imo it would be better if you pressed where you wanted to go with the mouse.
2. The offset is a little bit weird, I would make it so that it's focused on the player, instead of offsetting it to the left.
3. make the shadows stay even after you jump, there is a setting in unity for this, but I forgot which one it is.
But those are all minor nit picks, and considering that this is your first 3D game, you did amazing :D