I got it!!!! :DDDD
This is honestly such a good concept for a game, always thought vending machine mechanisms were cool (like the different ones in Japan and such) and I really think an idea like this could pop off hard on Steam. If this were expanded in some way where the design of the machine had a glass wall of the outside world I think it would strengthen+solidify the concept a lot more (just throwing ideas cuz I like the game idea that much, not really a critique). For actual constructive criticism though, I do think some way of easing the player into the game would help out a ton, like introducing under/overpayment only after the player has done a few orders and such. Another thing is that the coin system is a bit tedious when you take an order that involves a lot of them, such as recieving a dollar coin and trying to make change for a 15 cent item purchase. Regardless, I liked the game a ton and would totally wishlist the game if it were on Steam. Great Job!