The Canary's hideout is in an apparently abandoned clock tower. In the DC comics, Black Canary, along with her partners Oracle and The Huntress, make up The Birds of Prey. Their base of operations is a clock tower.
When Roy first meets Sin, she says "Back off Abercrombie" Colton Haynes who plays Roy Harper used to model for Abercrombie and Fitch.
Felicity notices a van from Metamorpho Chemical in some security camera footage. In the DC comics, the character of Metamorpho, the Element Man, is a hero who has the ability to control all of the chemicals that make up the human body.
Barton Mathis, The Dollmaker, is a new character in what is known as The New 52, a reboot of all of DC's comics. The number 52 is alluded to numerous times in the episode, being the room number at the hotel Mathis was staying in, and when Lance yells Delta Charlie 52 into his walkie-talkie when Felicity is abducted. In the phonetic alphabet, Delta Charlie 52 would translate as DC 52.
The name of the ship off the coast of the island is "Amazo." This is a reference to the Amazo, Professor Ivo's robot, which has been part of the Injustice League.