This is a really interesting genre to make a jam game for, as it reminds me of real-time strategy games where you have many different units across a map and have to micromanage them to make sure everything is functioning as expected. The difficulty scaling is very natural, as you start with one and can gain more vending machines, earning more money, but also having to control all of them simultaneously without getting them to break. There's a lot of UI work in here which is nice since from experience it's pretty hard to get decent UI that works. That said, the biggest point of improvement that this game could make is pacing. I feel that generally, the pace should be determined by the player and at no point should waiting be a central mechanic of the game unless it's an idle clicker or some other special case. In this case, you don't have any decisions to make when customers are not around, so the beginning is a little slow. Other than that, it's a neat concept, and it would be cool to see more of this genre in jams