Picked this up a few days ago. It's really really good. Like all the best bits of the minecraft tech mods, put together into a format which manages to remove most of the annoyances from the minecraft tech mods. For example, unlike minecraft tech mods, it doesn't need to worry about unbalancing tons of other gameplay or slowing down your game's ticks, and so is perfectly free to let you do crazy stuff (with no slowdowns yet so far as I can tell).
Pretty much the entire game will consist of you building your factory automation system, reworking it, ect; while putting up automated defenses to keep the biters out so they don't bite everything. Progression feels really like progression; once a setup is built, you don't need to think about it again until the rest of your facility is pulling more resources than it can process. Starts out with just manual mining; though that ends within a few minutes, most of which involves hauling coal back to your machines or smelting ores. A good deal later, vehicles and drones get involved, allowing you to put together places far away from your home while still being a short ride away. By this point you will also be hunting down the smaller nests of baddies to make room for Progress. So, uh, yeah, if that's your thing, try the demo or buy it.