The graphics are quite cute :) And interacting with the money was nice, I would just revert it. Instead of taking the money out of the customers pockets (this felt a bit awkward) I think it would be nice if they gave you some money and you have to give out the change :)
And I think reducing the time in later orders could be interesting. At the moment it felt like the timer was always similar. More time in the beginning and shorter time after some orders could create an interesting flow where you have to get better to get a higher score before the time runs out.
All in all a cute little game.