Here we have a very complex and rewarding episode that is actually three episodes for the price of one. Interestingly, each part is satisfying in its own way, and the whole is even greater than the sum of its parts. There is one key creative decision which nearly unravels the whole episode for me, though it might not for someone else: I don't believe the Gorn.
So let's start with the many ways in which this episode succeeds. The arrival at the destroyed outpost is as effective a teaser as Trek ever had. Laughter and merriment (albeit somewhat forced) gives way to battle instantaneously, and the viewer is drawn into the thick of the episode premise. It's a nifty dodge around the more typical distress signal cliche, and provides a much bigger bang because of the surprise.
The battle on the planet is remarkably well done, with some exceptional stunt double work that makes one want to freeze frame and zoom in to see if those really are Shatner and Nimoy running near the exploding pyrotechnics (it's not them, but very well-cast and well-photographed doubles). The staging is also restrained enough that no one has to do anything implausible or heroic, they simply do their jobs. There are two "red shirt" killings, but this is a rare instance when it does not seem gratuitous. The dialogue is strong, and the whole thing is beautifully photographed. Part of the success also comes from the elaborate set for Cestus Three, which is believably charred and broken, with battle scars and wisps of smoke everywhere. Dropping our heroes unexpectedly into such destruction is a sign of great confidence in the material and the viewer.
The second part begins at 10 minutes in, when they return to the ship and begin to ask quesions about what has happened. It's a combination pursuit/discussion segment which asks some hard Trek questions (about sentient beings, for example), and gets some very hard answers. Coon has written beautifully for the characters as Kirk and Spock confront differences in temperament between them. Nimoy is especially effective as a calm Spock in the midst of an adrenaline-driven chase. Shatner manages to successfully convey a captain who recognizes the issues but has made his decision. There are two dynamite Kirk/Spock exchanges which demonstrate the range of their relationship, as well as Spock's very specific responsiblities (raise issues, but implement Kirk's decisions even if he disagrees). Spock even says "Jim" in a call to their friendship, but is rebuffed by a Kirk who knows what he has to do. (He even borrows a line from the series bible about being the local police.)
The pursuit of the Gorn ship is surprisingly effective, given the fact that we never see their vessel. The audience is drawn into the frenzy so successfully that it's almost a disappointment when the battle is cut short before it can begin. It's another clever device. The disappointment is quickly turned into anticipation as we realize that a much more personal battle will take place. Coon is at the top of his game here, and each plot twist is unforeseen.
Part three begins at about the halfway point, the very end of Act II. Kirk and adversary square off on an appropriately desolate location, with very photogenic rock formations. It's unfortunate that scenes shot on the soundstage had to be intercut to cover gaps. There's really no way to match sky and lighting between the two, and it becomes a distraction. It's also unfortunate that the styrofoam boulder had to make another appearance, given how difficult it is to get it to blend in with the rest of the scenery.
Much of the battle is without dialogue. Long segments are action only, and the translator (called a "transicator" in the script) becomes a nifty device to break the silence every now and then. One missed opportunity would have been for the Gorn to use some nugget of knowledge obtained by listening to Kirk (who doesn't realize he's being heard) to his advantage. As it is, it's just a way of allowing Kirk to solioquize and break the silences. Music, much of it from Courage's scores for the two pilots, is used to maximum effect and works very well.
Back on the ship, Kelley has a challenge as McCoy has been written a bit more irrational than usual. Given the obvious futility of their situation, it seems a bit unreasonable for McCoy to demand that Spock use some logic -- as if thinking hard enough will break the long-distance tractor beam. Of course, he's just a vessel for backstory and dramatic heightening. It's unfortunate, however, when character takes a back seat to exposition. There are a couple of clunky moments like this scattered throughout this script, but they are generally bearable.
The major disappointment, as mentioned above, is the Gorn costume. Though it matches exactly the description given in the script, it looks a bit like it's on the wrong TV show. In that era, and in the time allowed, it was not really possible to make the costume any more expressive. But the frozen mouth and bug-eyes are more or less a constant reminder that it's a stunt man inside a rubber suit. The intent, as indicated in Kirk's description of the creature, is to invoke primal fears. But it would take a much greater attention to facial expression to actually accomplish this.
In addition to seeming a bit hokey, it's hard to imagine the creature as Kirk's equal in intelligenace and cunning (unlike, for example, the Romulan Commander from "Balance of Terror"). Intelligence is typically read in the eyes, and the creature reads as completely blank in this regard. Even when his actions turn out to be clever, it's hard to fear -- or even respect -- the Gorn. His vocalizations also work against him, sounding somewhat cartoonish. And he moves and reacts so slowly that it's hard to imagine him giving orders during a battle.
This problem is strictly due to the realization of the idea, not the idea itself. The entire battle sequence is very well written and staged. Without knowing what resources were available, it's easy to imagine a serpentine creature made with prosthetics and make-up -- sort of a green Klingon, perhaps -- thus allowing an actor to create the cunning with facial expression (if not with language).
The optical effects are somewhat disappointing throughout. Both phasers and photon torpedoes have a different, and rather static look (perhaps to change the color from blue to red, the only reason I can think of which would have prevented them from using stock shots). Also, there is a very noticeable jump cut during one of the bridge viewscreen shots -- as if they got to the end of one reel of star footage and the loop started over. The Metron effect, despite being attractive, is something of an odd choice. Coon's script describes it as "a twisting, confused mass of color and lines, as if some extremely powerful force is interfering with (the view screen)." In other words, he envisioned futuristic video snow. The result as realized looks more like a representation of the Metrons, which is a bit confusing when they turn out to be robe-wearing youths.
The Metron appears to speak out loud the message of the episode (as if we did not already get it). This is a bit of an annoyance, but mostly because it became such a cliche later. Superior races pop up all the time in Trek, and they usually seem to need to point out just how superior they are. So it leaves a bit of a bad taste after all of the excitement of the rest of the eipsode.
But it's easy to forgive the weaknesses because the script as a whole, along with the acting, directing, and cinematography are so strong.
Rating: Middle-Upper (3)