Get the free demo, then try the game, then come back and buy it because this is one of the best value for money deals you can ever get in this market.
Factorio has easily gotten a hold of my time and priorities. Married people and/or parents: fair warning! This game will drain your schedule and upset your social life.
You are stranded on an alien world. You only have your basic tools and technology. You start mining resources with dreams of manufacturing a vessel to help you get back to civilization.
Soon, you will start making things, that will help you make more advanced things, that will automate the making of old things, all the while deciding your own path through tech evolution, your energy needs and firepower. Yes, you will need defenses in place, because there are some living things that will try to stop your sprint towards domination over nature, with their agile bodies and their fangs and their teeth. Because nobody likes the tree cutting and the pollution you're causing. Plus, it will take some time to set yourself up with some nice, "clean", nuclear power.
Factorio is a mix of RTS/city building/puzzle/choose your own adventure kind of game where I have invested more than 500 hours in and I'm recomending it to anyone with even a slight preference to the genres I just mentioned. The price to fun ratio is ridiculous.