This was supposed to be the only episode with Felicity Smoak but she had such good chemistry with Stephen Amell she became a series regular.
One of the names tattooed on Deadshot is Glen Winter, who is a director of photography on Arrow.
Oliver asks for a man named Alexei Leonov. There is a real person named Alexei Leonov, he was the first person to "walk in space".
This marks the first full appearance of Yao Fei.
The four clearly visible names in Oliver's notebook this episode (Ken Shane, Mark Piler, Yazmin Soze, and of course James Holder) all appear on Deadshot's body, as well as many names that bear similarity to partial names in Oliver's notebook. Ken Shane is the second unit director for Arrow.