YMMV / Factory idle

• Difficulty Spike: The difficulty for each chain tends to steadily grow, however when you get to tanks, things take a hard turn towards complexity. To behold, tanks require a three-step assembly process, the "turret" stage requires lots of guns and steel, the "hull" stage requires more steel as well as electronics, and the "assembly" stage requires engines. You will need a massive assembly chain to take care of all that, probably lowering the amount of chains per factory to just one or two. And that's before we get to diesel and rockets...