this was fun!
My only real feedback would be that the layout of the UI layout is a bit confusing.
Because your stand is on the right and the customers approach from the left, I would recommend re-shuffling things so that all the customer side information (drink request, money offered) is displayed on the left and all the player side information (queued drinks, change) is displayed on the right.
the 'window into parallax' effect on the title logo is awesome!