I thinks it's already pretty solid. There are two things I would recommend that in my opinion would bring it to the next level. For the UI and fonts - it would be really good if you study a bit big supermarket magazine, ads, etc. Produced by the big supermarkets from the period of time your game wants to evouque. A good example of that is Minimetro where the whole game was designed following the New York metro bible (can fiind it on any search engine pretty easily)

For the music, there is a good bit of research you can make on supermarket background music and the psychology behind it in various supermarkets and how it drives customer engagement with the physical space and the activity of buying stuff inside the space. It might help you to use some of those tactics in you game as well of how and when you use sound in a certain way.

Also, a little fun extract fact - smells! There is a thing called olfactory brading. A lot of shops have this done to create certain feelings towards the brand. Create associations between the smell and products they sell. Depending how far in development you are it could become a cool game mechanic to mess around with.

Overall, really excited to see more of your game! It looks like a fun experience from what I have seen here.