Mirror Hoshi: (upon arriving to Earth) You are speaking with Empress Sato. Prepare to receive instructions.
Mirror T'Pol: I'm surprised you're not exhausted from all the beds you've jumped into recently.
Mirror Hoshi: Commander Tucker told me I should give you a few pointers in that area.
Archer: Great men are not peacemakers. Great men are conquerors!
Reed: Perhaps it was a pet owned by one of the original crew.
Phlox: Unless one of them owned a velociraptor, I find it extremely unlikely.
T'Pol: It may take centuries, but Humanity will pay for its arrogance.
Hoshi: These people had some strange ideas about uniforms.
The CGI Gorn encountered in this episode is radically different from the one previously fought by Captain Kirk in the TOS episode "Arena". The original slow moving Gorn having insect like compound eyes and no discernible tail.
The final battle between Phlox and Tucker was scripted originally to be filmed in the Emergency Manual Monitor, a room overlooking Main Engineering. However, the expense of building this set, and the CG effects showing Engineering through a window, demanded the scene be moved elsewhere.
Bobby Clark, who played the Gorn Captain in the Star Trek: The Original Series episode "Arena", was on set during the filming of Archer's fight with Slar. Clark was a guest of Enterprise stunt coordinator Vince Deadrick, Jr., the son of Vince Deadrick, an actor and stuntman who appeared in numerous episodes of the original series.
As of this episode, Majel Barrett has appeared in, or been the computer voice for, all five live-action Star Trek television series.
References 1 Corinthians 13:12(ASV), "For now we see in a mirror, darkly; but then face to face: now I know in part; but then shall I know fully even as also I was fully known."