Others have already praised this episode for its unique camera angles, and other technical aspects. But there are also script elements that elevate this episode above others in the series. As the episode opens, we hear "Dave Bailey" carping about how bored and fatigued he is after three long days of "star charting". This brilliant line shows us that between "adventures", the Enterprise and its crew are actually doing something productive! Another element is the phaser drills that Kirk has the crew run. Once again, they are keeping busy. Also notice the constant background chatter over the intercom system (a feature that would slowly disappear as the seasons progressed). With this episode, one gets the feeling that this is a "working" vessel and crew (as opposed to nothing but plywood sets) - aspects that would be completely lost by the third season.