Sam and Dean, as agents, tell the woman at the bus their names are agent Stark and Banner. Stark and Banner are the last names of Marvel characters Tony Stark and Bruce Banner; Iron Man and The Incredible Hulk, respectively.
When Sam and Dean are in the quarantined area to rescue the other hunters, they pass by Ozzy O's Diner, a possible reference to Ozzy Osbourne, lead singer of Black Sabbath.
Kevin identifies himself on the phone as Kevin Solo - a reference to Han Solo from Star Wars: Episode IV - A New Hope (1977).
The music that is playing in the background when Ezekiel kills the demons is the same music playing in the background during the rescue of Samandriel in 8.10, Torn and Frayed (2013)
When Dean enters the bunker, Kevin shoots at him with a crossbow. Dean calls him Katniss, it is a reference to Katniss Everdeen the main character of The Hunger Games who is an expert archer.