A much younger Genevieve Buechner - who played Samantha in this episode - previously appeared in the Season One episode "Bloody Mary"
When Sam and Dean first visit the comic book store, a figure wearing a Red Hood mask is briefly shown. This is clearly a nod to Jensen Ackles who voiced the Jason Todd/Red Hood character in the animated movie "Batman:Under the Red Hood".
Some of the scenes shown from various horror movies/trailers come from previous episodes, including the ghost truck from Route 666 (Ep 13 S1), and a shot of a young John Winchester walking up to a vehicle in a repair shop from The Song Remains the Same (Ep 13 S5).
At the beginning of the episode, there is a poster on the wall of a movie called "Hell Hazers." This is a reference to episode 18 of season 2, "Hollywood Babylon"
There is a "House of Wax" poster right behind the Red Hood when the brothers first walk into the store. The poster is for Jared as he starred in the movie and the Red Hood is voiced by Jensen.