The movie that 1986 Ulrich talks about with Hannah in school is Breakfast Club
The console game Jonas and Bartosz are seen playing is The Surge (2017) by German developer Deck13. Although Jonas and Bartosz appear to be playing a 2-player cooperative split-screen version of the game, the released product does not contain this functionality. When asked on reddit, one of the developers explained that the 2-player gameplay shown was faked; at the time the footage was included, the game was not yet completed. The show's producers decided to fake the 2-player gameplay as it suited the show's narrative better.
The postal code written on the package that The Stranger has delivered to Jonas is 36177 - this indicates that Winden is located in the central German state ("Bundesland") of Hesse (though the postal code itself, like the town, is fictitious). The people of Winden also use the colloquial word "nee" (meaning "no") rather than the more formal "nein", which is what central Germans are known to do.