The ranking in this list doesn't say anything about the film, many of these films I haven't even seen. The order is solely based on the artwork of their Polish film posters. You can access individual posters from a link in the notes. (Imho it is very unfortunate that Letterboxd doesn't allow us to embed pictures.)
Alternatively, you can browse the whole album of Polish movie posters.
More information about the history of Polish film posters:
The Legacy of Polish poster design by Andrea Austoni
Cinema poster - a site dedicated to information about Polish poster.
Quote: "late 60s seem tired, 70s - flat and uninspired, 80s - repetitive and boring and the 90s nailed the coffin shut"
Polish poster - a poster merchant with a huge collection awaiting your exploration
A video (actually the beginning of a feature length documentary) about the history of Polish poster art