Like "The Return of Archons", this episode presents a false paradise for Kirk to battle, this time by himself. With spores infecting the crew, "Paradise" is really a not-so-subtle metaphor for drugs, a bold statement for a show that in its original day had a large hippie fanbase. In its stucture, the episode is simliar to "Shore Leave", taking place largely outside and placing the emphasis on the regulars over the guest stars (with the exception, in this case, of Jill Ireland playing a love interest for Spock).
With the crewmembers literally abandoning ship to live in peace on the planet, Kirk is forced to ask himself if a captain without a crew is still a captain. Even his reliable righthand man, Spock, no longer listens to him, giving the episode a substory more fans remember than the main one, despite it largely happening offscreen. (That's because it hits all right notes, allowing Nimoy to be himself, giving a great visual of him swinging from a tree, and feeding into the dreams of fangirls who have always wished to melt Mr. Spock's cold It also marks the transition of Spock's people being known as "Vulcanians" (mentioned quite a few times in the first season, including early in this episode) to Vulcans (with Kirk calling him such later in the episode). The transition continues in "Errand of Mercy", with both terms being used again.
As an outdoor adventure with the crew cutting loose and having fun, "Paradise" is one of Star Trek's more memorable adventures; but the truth is it's slow moving with little action and probably more of a middle of the pack offering for the original series.
Remastered: With the original version putting its money into location shooting as opposed to effects (reusing shots of the Enterprise in orbit from "The Man Trap", with the planet tinted green), there's not much for CBS Digital to do here. They do, however, create a beautiful Earth-like planet, complete with visible radiation, and show off some beautiful establishing shots of the ship.