Is the Gorn really that slow? Surely, I must be exaggerating.
Well, they're so demonstrably slow that Kirk's Gorn adversary is forced to literally plead with him to stop running away so he can kill him. He even throws Kirk a bone and tells him he'll be merciful. Gee, what a guy.
What's this about dressing like Barney Rubble?
I'll let you come to your own conclusions.
The episode begins with the crew of the Enterprise beaming down to Cestus III as the guests of Commodore Travers, the commander of the outpost situated there. Upon their arrival on the planet's surface, instead of the delectable victuals they were expecting to dine on, they find smoldering ruins and discover that the outpost's inhabitants have been killed with the exception of one survivor. Soon afterward, they come under attack by the beings who are presumably responsible for the massacre. During this battle, we hear mention of the attackers moving from position to position in a bid to outmaneuver the Enterprise men and secure the high ground, suggesting a furtive, tactically adept enemy that is fleet of foot.
The Enterprise crew succeeds in driving off their attackers and they give chase in the Enterprise as the perpetrators of the massacre (later identified as the Gorn) flee in their own vessel.
At this point, both the Enteprise and its quarry run into the Metrons, a race of super-beings who are a bit upset that savages are running loose in their neck of the woods and actually trying to kill each other. Determined to put an end to these shenanigans, the Metrons transport Kirk and his Gorn counterpart to a desolate planet and tell them to have at it and kill each other. Both Kirk and his Gorn adversary are unarmed but the Metrons hint at the possibility of manufacturing a weapon from items found on the planet's surface and inform both gladiators in this crude arena that the survivor (and his crew) will be permitted to go on his way while the loser will, of course, be dead but he won't be lonely for long since the Metrons intend to destroy his crew.
We're then treated to half an hour of Kirk running away from the Gorn, which is revealed to be incredibly strong but also incredibly slow. In fact, the Gorn is so slow that one could envision this “battle” lasting for days if only Kirk's stamina can hold out.
It seems it cannot, so his only chance at survival is building the weapon hinted at by the Metrons, since beating the Gorn to death with the plethora of sticks and stones available on the planet is not possible since the Gorn seems to be able to take whatever the Captain can dish out and then some.
The Metrons appear to possess the sort of sadism that only super-beings in the Star Trek universe seem capable of so they provide the crew of the Enterprise with a ring-side seat in the proceedings, allowing them to observe their captain slowly getting worn down by his adversary's relentless (if sluggish) pursuit.
It is at this point that Spock notes that the ingredients for gunpowder (sulfur, potassium nitrate and coal) are available in plenty on the planet's surface and we get to listen to him creepily intone “Good...good... ” (in a manner foreshadowing Buffalo Bill's rather disturbing delivery of those same words) as he observes Kirk noticing the same thing and taking action to construct a crude fire-arm.
To make a long story short, Kirk builds the gun, shoots the Gorn and then spares its life, thus winning the approval of the Metrons who send a representative in human guise wearing the sort of outfit that usually destroys acting careers to smugly inform Kirk that while his race is still savage, there is hope for humanity, yet.
Frankly, there is much about this episode that just rubbed me the wrong way. With the exception of Kirk, the Enterprise crew doesn't really do anything. McCoy scowls, Spock provides exposition and Uhura screams at the sight of the Gorn, but beyond that, the crew of the Enteprise merely stands by and helplessly observes Kirk's heroics. The behavior of the Metrons was also particularly annoying. If they're the super-beings they're supposed to be, they must realize that less “enlightened” species will often behave in a less than enlightened fashion. What is to be gained by interfering in their affairs and arbitrarily forcing them to take part in what is, for lack of a better word, a cockfight?
For a bunch of super-beings they're a lot closer to the “savages” that they so smugly disparage than one would think.
Maybe that, in itself, is the point of the episode.