Yeah, lots of plot holes and cheesy special effects but this is one of my favorites, and it's entirely due to Shatner's restrained (for once) performance. He actually seems to be acting and responding to the crew (mainly Spock) like a normal human being without any of his typical over- the-top hamming it up. Well, with the exception of the ending where, sadly, the writers reverted back to the cutesy crap. I can't really blame Shatner for that, either. When given decent dialog in the rest of show, The Shat did alright in this one, making it one of the most watchable episodes.
And a shout-out to user verbusen for noticing Lt. Leslie in his review. After rewatching these episodes many times, you start picking up the small things in the background, and Lt. Leslie at the helm next to Sulu, as well as wearing a gold tunic (as opposed to his typical red) is unusual. What isn't unusual, of course, is that Leslie has no lines. It's worth noting that the actor who played Leslie, Eddie Paskey, made a point of actually reading the scripts beforehand so he knew when an anonymous red-shirt was going to get offed, and made a point of making himself scarce during those red-shirt casting calls.
And a shout-out to user verbusen for noticing Lt. Leslie in his review. After rewatching these episodes many times, you start picking up the small things in the background, and Lt. Leslie at the helm next to Sulu, as well as wearing a gold tunic (as opposed to his typical red) is unusual. What isn't unusual, of course, is that Leslie has no lines. It's worth noting that the actor who played Leslie, Eddie Paskey, made a point of actually reading the scripts beforehand so he knew when an anonymous red-shirt was going to get offed, and made a point of making himself scarce during those red-shirt casting calls.