Fontana must again be getting credit just to get paid, because the work is far beneath her capabilities. This is either a 50's B-movie, or a 90's sitcom, you choose. One way or the other, it is very unfortunate Trek.
The aliens are from an implausible place, on an implausible mission, with completely implausible tools. I bet those belts can unclog drains and even send text messages! Worse, after 45 minutes of looking utterly unstoppable, they are felled by Kirk's words -- which are simply being repeated from Act I. Why they work now after not working then is the biggest mystery of the episode. In fact, in a quick fix to beat all quick fixes, they agree to settle on the very planet they proclaimed to hate so much at the beginning. The aliens never rise to the level of Star Trek. They belong in, ahem, Lost In Space.
Our characters go through their regular routine: trick a guard into letting them out (with the help of a mind meld and a karate chop), get caught, then try again with the old "this guy's sick" routine. At least, we must admit, these activites force a pause in Kirk's uncharacteristically self-pitying approach to the dilemma. The whole "a captain cares for his crew" schtick has now officially worn thin.
The episode also does a clunky about-face from high drama (too high) to low comedy over the course of a single scene. The about face -- from being terrified and powerless to getting drunk and kissing -- takes all of about 30 seconds. The scene itself may be the best in the episode, but what it does to the whole tone is inexcusable.
What saves this episode from ranking with the worst of all episodes are the costumes (which at least allow us to not ridicule the aliens), and the nifty concept of reducing a human to a small chunk of chemicals (along with an unusually cruel red shirt execution). It only gets a mention, and might have made a solid base for a more interesting character-driven alternative to this story.
Rating: Bottom (6)