The fictional arcade game Polybius of urban legend appears in the background of the bowling alley with an out of order sign on it.
Cruel Summer by Bananarama plays while they are riding their BMXs. Exactly the same positioning in the Karate Kid with Daniel LaRusso riding his BMX to the same track. A cool nod considering it was released in the Summer of 84.
When the boys are in the clubhouse talking about Nikki, Tommy is seen drinking a bottle of MacReady's Whiskey. This is a nod to The Thing (1982) where Kurt Russell's character, R.J. MacReady, drinks J&B Scotch Whiskey at different points in the movie.
When Davey cleans his closet, just before finding the G.I. Joe's walkie-talkies, you can clearly spot a figurine of Turbo Kid, the title character of RKSS Films previous film, Turbo Kid (2015).
One of the photos of the missing boys shown is that of a victim of John Wayne Gacy.