This should be a great episode. It's a fine sci-fi premise (losing a shuttlecraft inside a swirling space cloud), a great opportunity for character interaction (stranded, stressed, desperate, under attack), and it's all about the people interacting (Scotty's tech solution is mercifully simple). But almost nothing clicks, primarily because the script simply doesn't sing.
Perhaps it's best to view it within the larger picture. This episode reinforces some things that we already know about the characters, and it has value in this regard. When writing it, they knew that not everyone in the audience had seen last week's episode or would see next week's. This explains some of the repetition and some of the reduction of the characters to types. In terms of "creating the series" this episode could be considered a success.
But as a piece unto itself, within the spectrum of Trek quality, it's a pretty miserable failure. Spock is forced to reason and think out loud. He's challenged every step of the way by lower deck crewmembers who don't fit the type of crew that we've come to know aboard the Enterprise. McCoy is there as a foil only, with nothing to do, and no real reason for having been on the assignment in the first place (his accusations about Spock and command simply don't ring true to either character). And there's another yeoman-of-the-week who looks good but really is there just to be scared ("I don't want to die up here.").
And then there are the creatures -- unfortunate tall extras in big fake-fur coats throwing styrofoam spears which seem to bounce off of everything. One has to believe that if you saw one of these coming you'd just step out of the way. If you didn't see it coming, you'd rub the spot where it hit and say something like, "Hey! Cut that out." And then there's the giant styrofoam boulder. There are some very bad production values here which just cannot be forgiven.
At least they got the fog right -- except for the weird optical fog which was likely added after the fact to cover a dead body which caused objections from the censors. There are many optical effects (this episode must have cost a fortune) and quite a few are very, very sloppy. The first one, of the glowing cloud, is great but it's all downhill from there. Eventually the bridge view screen shots have a very ragged quality about them and a visible edge on the left. The shuttlecraft sequences, even for that era of low-tech effects, look especially cheesy -- as if the model is about six inches in length. It never moves plausibly. A better solution would have been to simply eliminate most of these shots and written around them (the creative team did this a lot on other episodes, and it's a mystery why they did not here, unless that model cost a fortune). After establishing the craft leaving the ship, we could have done without most of the space exteriors until Spock lights the fuse.
The shuttlecraft bay miniature, on the other hand, is quite spectacular, despite the fact that the stars seem to be constantly shifting just beyond its opened external door. And the incoming shuttlecraft seems to land on the very edge and never move completely onto the hangar deck (certainly a limitation of the model).
There's not much to say about the guest crewmembers. They seem roughly interchangeable, and the performers do what is asked of them -- which is unfortunate. Phyllis Douglas as Yeoman Mears is distinctly underwhelming. Our regulars perform competently, but there's nothing complicated required of them. Emotions are written so starkly that only freshman level acting is required.
Nimoy has the greatest challenge: finding Spock in this mess of a script. He nearly gets it, but the reasoning-aloud requires him to be something that Spock is not: a motor mouth. It's also inexcusable to write Spock as insensitive to the grieving needs of his fellow crewmembers. Much more headway would have been made if the crew feared he would respond badly, but then he responded with compassion. Of course, it's also inexcusable to write his fellow crewmembers so harshly.
It equally inexusable to include a tag which leaves everyone laughing (forced laughter, no less) at Spock's expense. Interestingly, this is not in the script and must have been added on the set. Relief from the episode's tension is appropriate, but ridicule is not. This scene is again outside the range of the characters we have come to know. The Enterprise crew has been characterized repeatedly as a group which pulls together -- not unravels -- during adversity. In this regard, the very premise of this episode is un-Trek.
Rating: Middle-Lower (5)