The game has a great atmosphere!!!
It took me a while, including reading the comments, to get the game.
I think I encountered a bug that made it too tedious to finish the game. You can process many resources in every production step, but not in the smelter. When you put a few resources into the smelter, it always produces 1 ingot, and if you put 1 resource into it, it also produces 1 ingot.
For everyone wanting to know some tips:
The game has four screens that can be rotated by clicking on the top left or right corner.