This is a nice attempt at post socialist nostalgia.... I think the most authentic part of it is the terrible service (long wait, disorganized, with attitude). The food is adequate although does not do justice to delicious authentic home cooked Polish dishes. My favorite were "golabki" (cabbage rolls) made with cubed rather than ground meat. They seemed to have a South American flair. They were served undercooked but tasty.
There are too many items on the menu to be made fresh as most are quite time consuming. But that is just an unconfirmed theory based on personal experience with Polish cuisine.