When Will (Noah Schnapp) is trying to get Lucas (Caleb McLaughlin) and Mike (Finn Wolfhard) to play D&D, the song he plays on the radio is from The Dark Crystal (1982), the Pod Dance scene, which was composed by Trevor Jones.
This episode takes place on July 1, 1985.
Eleven (Millie Bobby Brown) and Max (Sadie Sink) find Billy's (Dacre Montgomery) bathtub filled with ice. When Will (Noah Schnapp) was possessed by the Mind Flayer in season 2, he wanted to be kept cold.
When Max (Sadie Sink) and Eleven (Millie Bobby Brown) turn up at Heather's (Francesca Reale) house the number on the mailbox reads 1438 which is only one digit different to Nancy's (Heather Langenkamp) house in A Nightmare on Elm Street (1984), which is 1428. It's also three off from 1408 (2007) which was based on a Stephen King short story. The Duffers (Matt Duffer and Ross Duffer) were heavily inspired by Stephen King when creating the show.