Something that would really help in the late(r) game would be someway to chain furnaces (and other machines) together, meaning that they would balance whatever they have in them. Currently if you have a bunch of one item that you wanna distribute between 4+ furnaces it is extremely annoying. It would be cool if you could for instance colour the furnaces and that would link them, or it could just be if they where next to eachother they would chain. Alternatively this could be a skill that would come after automation or engineering skill.
Another thing that might help, would be if you could somehow choose more precisely how many item you wanna put in / use at a time in a machine. A tool tip that somehow tells you how much your items sells for might be nice, kinda like how you can see what they cost (this might already be fixed with the new UI showcased in the dev video?).
As someone who enjoy some more "organised" farms, it would be nice if you could somehow designate areas. Or at least make it so natural growth doesnt happen there. For example: I wanna make a berry farm, so i designate it so only bushes can go there. You could then also add berry seeds or a way to move the bushes, so i could actually make a berry farm. If there was also a more specialised "mining pillar" that didnt destroy the bushes that would help even more.
Some other nice to have things could be a structure that sucks item in and store them (for the mining pillars, to decrease lag). A "seedbag" or something similar that lets you plant 2x2 etc. Landfill acts like bridges but they look like land, so you can essentially make a large island. Landfill should be expensive, 20 stone?
Well thanks anyway for a nice game, even if it is only at the demo level currently :) Keep up the good work.