Automachef is the most unique factory game I've ever played. You make factories to handle food orders, try to reuse as many parts as possible to save cost, figure out how to handle massive rush hour mobs without burning too much power or dropping orders, and so on.
Down the line, this game has its own coding language for controlling machines and handling orders. It's got a puzzle campaign, and a whole contracts mode, all around a good time. You can make VERY tight factories, especially with late game tech.