The second episode to be directed by Tom Cavanagh (Harrison/Harry/H.R. Wells), the first one being The Once and Future Flash in Season 3.
While searching Ralph Dibny's office, Iris West Candice Patton discovers a bottle of "Gingold" soft drink in his desk drawer. This is a direct nod to the Elongated Man's comic book origins. Gingold is a fictional soda in the DC Universe, and widely drank by the "india-rubber men" from carnival sideshows who fascinated Dibny. He distilled the raw essence of the main ingredient (the rare gingo fruit), and the extract gave him the power to contort his body.
Mayor Bellows says he was once a police officer at Central City Police Department, a reference to the original The Flash (1990) series where he played Officer Tony Bellows.
In the scene where Cisco is in Star Labs hiding from Breacher (Danny Trejo). Cisco is gathering weapons as he is not allowed to use his powers during "The Hunt". One weapon he picks up is a machete. This is a reference to Danny Trejos character in the "Spy Kids" and "Machete" films writen/directed by Robert Rodriguez.
The character of Ralph Dibney was previously listed as one of the people that had been killed during the particle accelerator explosion that created the Flash and most of the other Earth 1 metahumans (according to Dr. Wells/Eobard Thawne in episode 1x7 "Power Outage").