A really cozy and promising demo. Initally I struggled to understand how the theme of shadows would fit into the game but from reading the GDD I think I have a much better grasp of what a more complete product would look like.

I think the primary gameplay loop is really strong and offers a lot of potential. It reminds me of Slime Rancher in that sense where you have a primary base, but are encouraged to venture further and further out in order to get the resources you need. I can also see a lot of potential for player expression with decorating your space alongside placing machines to automate the process of ore refinary if you want to go down more of a Factorio route for development.

The artsyle is really well realised for what you were able to do in the time. I think the player avatar is really cute! They remind me of Ralsei and I would be interested in seeing them developed as a character more if you are interested in making them more than a silent protagnoist. I also loved the choice of colour pallete you used for the enviroment; its saturated and vibrant but the use of purples and greens really sells it as an otherworldly enviroment.

Overall, even if the prototype is missing key features (I would have loved to know more about your plan for the shadow creature) I able to look past the lack of polish and see a lot of pontential in it. You've taken the theme and mixed it with a wide array of inspirations and created something that I would be interested in following further. Good job!