In my opinion, The fact that you cannot fire workers becomes semi-annoying late game. I could learn how each aspect/material used by your workers affected them in their own ways, environment bonus it seems to me like the work speed is slightly faster depending on the value it produces on the worker. I would like to see a sequel. If you have trouble getting money or anything similar, have small but relatively good projects while some staff are training. For example, I have my first 4 upgrading to final tier while i occupy my other workers with micro-small projects.