Took me about 14 days to beat it.
Nice game, what I find interesting is that you essentially play backwards at the end.
What I mean by that is that when preparing for the rockets, first, you spend all your wood, stone, iron and oil to make paper.
Then, you spend all your wood, stone, and iron to make oil.
Then you gather wood and stone, and spend it to make iron.
Then you gather wood to make stone.
So at the start you keep going forward in what resources you want to get, until you reach paper, where you start going backwards again to stock up on the earlier resources.