Kevin Smith talked about the experience of directing the episode on SModcast 350: Scan BC-ing Ya'! podcast. He described the experience as fantastic, giving a lot of credit to the whole crew saying he served more as an advisor/motivator for the team who, according to him, had it pretty much covered. He hopes to come back to direct more episodes.
Girder comes back as Zombie Girder in this episode. In CW's iZombie, the actor who plays Girder, Greg Finley, plays Drake Holloway, who is also a zombie.
On the April 18, 2016 episode of YouTube show Fat Man Beyond (2012), Kevin Smith admitted that directing this episode of The Flash was the "greatest directing job" he's ever had.
Cisco references Young Frankenstein when he refers to Girder as Abby Normal. Abby Normal is what Marty Feldman's Igor refers to as the person whose brain Dr. Frankenstein put into the creature.
When Harry says "First time as tragedy, second as farce." He is quoting from Karl Marx's essay The Eighteenth Brumaire of Louis Napoleon, which was originally in Die Revolution in 1852.