The factory must grow. That is the whole pitch, and it is enough. You crash-land on an alien planet, start by mining ore by hand, and end up presiding over a roaring automated sprawl of conveyor belts, trains and assembly lines that you absolutely did not mean to build at this scale.
Factorio is the purest just-one-more-thing game I have played. Fix one bottleneck, reveal three more. The locals are not thrilled about your pollution either, so there is a defence game woven through the logistics. It is engineering as a compulsion, and it is glorious.
Genuinely hard to put down. Consider this a warning.