TREKCORE > TOS > EPISODES > BALANCE OF TERROR > Behind the Scenes

	Mark Lenard, who plays the Romulan Commander, would later play Sarek, Mr. Spock's father in "Journey to Babel", "Star Trek: The Animated Series", "Yesteryear", "Star Trek III: The Search For Spock", "Star Trek IV: The Voyage Home", "Star Trek VI: The Undiscovered Country", "Star Trek: The Next Generation's", "Sarek" and "Unification, Part I" as well as the Klingon captain in "Star Trek: The Motion Picture".
	The Enterprise phaser blasts resemble the photon torpedo blasts that would later be used in episodes like "Errand of Mercy" among others. Since the Enterprise's phasers had already been seen as a traditional beam-like effect in "The Corbomite Maneuver", its possible that the phasers used in this episode are more like "pulse-phasers" that the U.S.S. Defiant would use on "Star Trek: Deep Space Nine". Gene Roddenberry pushed for more "projectile-like" weapons to create the illusion that the Enterprise and the Romulan ship were engaged in the type of battle two underwater submarines would have.