The song "Cry Little Sister", the theme song to the 1987 Vampire film The Lost Boys (the movie playing on the TV that entices Alex into the apartment), is heard twice. The first time, when Alex and Yasmin perform their science experiment, it is performed by original artist Gerard McMahon. The second time, when Alex and Yasmin are in the boiler room, it is a cover version performed by Chvrches.
The writing on the oven door in the gingerbread house reads "die kleinen sterne sind die kleinen lämmer /
Der Mond ist der kleine Hirte / Schlaf, Kinder, schlaf." which translates to "The little stars are the little lambs / The moon is the little shepherd / Sleep, children, sleep." The spelling has a couple of mistakes, also the text was apparently copied from an original print that used blackletter script, in which an s, for example, looks very much like an f.
Alex refers to himself as a "creepshow". Creepshow (1982) is a horror anthology film consisting of five short stories written by Stephen King.