The Rescue
As far as two-parters go, this one is definitely pretty high up on my list.
It's not a very complex story. Nor are the "stakes" in it all that particularly high. Which, in my opinion, is a good thing to do with the two parters back in the classic series. With the exception of "The Ultimate Foe" (believe it or not, my favourite of all the two-parters) - I've always enjoyed the two parters more when they don't try to give too massive of a scope to the story. Even "Edge Of Destruction" from the previous season suffers because it tries to be so dramatically intense throughout but isn't given much of a chance to "build up" because it's only two episodes long.
But "The Rescue" is an economical little tale that is mainly there to introduce Vicki and get her onboard the TARDIS. Yes, we have a bit of a mystery going on with some slight elements of suspense and intrigue. But they are, for the most part, largely inconsiquential to the overall thrust of the story. Fortunately, they're not too badly underplayed, either.
The "real plot" to the story is interesting enough. Two stranded earthlings being menaced by an alien is just enough storyline to fill the two parts. The twist at the end is quite nice too. Although, sadly, I had read in something, somewhere that Bennet was Koquillion and the surprise was ruined for me. But it seems to me that if I hadn't read the spoiler, I wouldn't have guessed the final outcome of the story. And that is a nice testament to the scriptwriting. Oftentimes, plot twists are not surprises because too many clues are given leading up to it. Not the case with The Rescue.
But the real emphasis of this tale is characterisation. This is laid out quite evidently in the opening scene with Vicki and Bennett as they give us a touch of expository dialogue to reveal their plight to the audience and, at the same time, create a certain degree of empathy too. Especially Vicki. She was always a very "bright" and energetic character without ever becoming annoying or tedious. Maureen O'Brien should be praised for her skills in crafting what was, essentially, "a new Susan". She made her radically different from her predecessor - even if the scripts didn't always serve her up that way.
But we see an even stronger example of characterisation in the next scene in the TARDIS interior. The Doctor is definitely shedding is anti-hero image here. Even the way they had him asleep as the ship materialised made him seem all the more vulnerable. And, therefore, likeable. One would normally expect his character to revert to some very crotchety behaviour as he regains consciousness. Particularly since he would be doing his best to conceal his sadness for saying goodbye to Susan. Instead, he's pleasant to his companions and even a bit tragic as he calls out for Susan and then remembers she isn't there. A really touching little scene that continues to set the real tone for this tale.
Again, the shortness of this story keeps the action quite tight. We don't have to bother with a whole lot of slow build-up since everything's got to get finished in just two parts. The fact that we're facing a rock-fall and a forced seperation of the TARDIS crew within minutes is a nice change of pace from the stories of this era. And this keeps the story interesting.
But we still get a lot of slower moments for all these nice characterisations to set in too. But never at the expense of the story. Rather, these moments enhance it. And they foreshadow quite nicely that Vicki will be coming aboard the TARDIS as all the characters "take" to her in different ways. The Doctor, of course, being the one who forms the strongest bond since he sees her, immediately, as a substitute for the grandaughter he lost.
The final confrontation between Koquillion and the Doctor in the Judgement Hall is, in my humble opinion, executed to dramatic perfection. The Doctor sitting with his back to Bennett and claiming he knows who he really is was a great way to start the scene. Even the fight sequence looks pretty good. A pretty big surprise since physicalities are generally handled by Ian. It all comes to a very good ending as a few surviving "Didosians" appear and save the day. And we're able to feel sorry for them in the later scene as they smash the communications equipment on the ship. The Doctor's description of them earlier in the story sets up a great sense of sympathy for them in their final scene since we understand that violence is repugnant to them but that the wiping out of their species has changed them radically. It's all very poignant. Particularly since the two characters never say a word.
So, all in all, a very simple little tale that serves up its purpose quite nicely. In much the same way as "Black Orchid" would, nearly twenty years later. And this, I feel, is the best way to "do up" a two parter. Some nice character moments and a story that doesn't try to do too much in it since it's over almost as quickly as its begun.
Great stuff.