I am extremely surprised that this episode is generally rated so low, as I personally consider it to be one of the third season's far stronger instalments.
Pint-sized Michael Dunn gives a very good performance as dwarf Alexander, who has been at the Platonians' mercy for countless ages. The character is very sympathetic, and Dunn plays the role perfectly.
The Ancient Greek concept had already been utilised in the second season episode "Who Mourns for Adonais?".
The way it is presented here, it seems as if Earth's Ancient Greek Gods were indeed real, and the Platonians encountered them before voyaging into space.
The plot is one of (if not THE) darkest of the Original Series, and has some truly chilling moments as Kirk and co. are used as the Platonians' playthings. The moment at the end of the second act, where Kirk is forced to act like a horse, with Alexander the dwarf riding on his back, and Kirk shrilling, is truly haunting.
Of course, this episode is famous for another thing – the kiss between Kirk and Uhura, often cited as American television's first interracial kiss. Many of the 'powers that be' were very unhappy about this, to the extent that some stations refused to show the episode. It seems ridiculous nowadays that something could have caused such uproar.
Here in the United Kingdom, this episode was typically skipped by the BBC on their repeats of the series, with the treatment dished out to the crew and Alexander deemed unsuitable by the Beeb for the show's timeslot; it became one of several episodes to be dropped from BBC runs of the series. However, since the 1990s, this episode has always been included on repeat runs.
This episode is also of particular note to me for getting me back into the series, after my interest waned slightly in the late 1990s – early 2000s. A few weeks previously I had found an old off-air recording of the second season's "The Ultimate Computer", and not long after, a friend lent me a film he had recorded, and which just happened to have a recording of this episode afterwards. These two episodes reignited my interest in the series.
Overall, I find this to be a very strong episode, and one that could easily have come from the far better second season. It has a good story with some very dark moments, and I don't think it deserves the low rating it has. From me, it falls not far short of a perfect 10.