Great concept and I could see this game selling well so I hope you keep developing it.
two thoughts on improvements:
1. The Upgrade tree is not immediately intuitive on what I can/can't afford. I don't believe the red/yellow outline is enough of an indicator compared to most games that just gray the upgrade out completely until you can afford to purchase it.
2. The initial "hover to interact" mechanic makes me believe this will be more hands off compared to a "click or click and hold to interact" mechanic. So when I was hovering over the book printer I was expecting the cashier to already be automated and vice versa. I think this would be solved by using a click to hold mechanic instead of just hover.
Again, love the concept so far and definitely interested in playing your future versions of this.