I've been following and on and off playing Factorio for several years. In one word: Addicting. The factory must grow. There are always problems to solve... more resources needed, more factories needed to consume them. More efficiencies to be gained. While there is a learning curve, it is well worth it and is unique and unbeatable in its scope. The developers have made a point to optimize just about everything so you can spend hundreds of hours on a factory without seeing a slowdown in performance. I definitely recommend this game.