The One where Kirk is split in half
Now, as bad as the last one was, this is top notch. It maybe suffers from that final 4th act that tends to drag out the story beyond it's natural life span, but that's being picky.
High concept time - what if Kirk was split in half, one good, one evil? We find out not as simple as we first thought. Some respect must go to Shatner here, who is easily mocked for his acting, but really delivers for the emotional, ego driven 'evil' self. He doesn't quite pull off the softer, logical side quite as well, looking a tad tired and anaemic really, but he makes this episode so watchable, you can't take your eye's off him.
Every one has a good part in this story. Spock and McCoy are great, debating whether to risk rejoining Kirk with his alter ego. Bones is all about the health of his patient whist Spock is fascinated by the potential of examining kirk, and also of the safety of the away team.
Ah yes, Sulu and extras, stuck on the surface, freezing to death. Why not just send a shuttle? 'Cos they hadn't been thought of yet. Best to assume there was radioactive clouds that would prevent reentry. Sulu does well here, making his claim to be a regular. Scotty is...Scotty, doing his transport chief part and making me believe that he knows this ship back to front with his diagnosis of the repairs and solution. He really should have done the reverse transport, but it gave Spock a nice scene as he looks...tense?! Nicely acted.
Uhura has gone missing in this episode, so her role is given to Rand, which features evil Kirk attempting to rape her in the cabin. Dark stuff for early Trek, even if Spock makes a joke about it at the end of the episode. WTF?! Surely it should be more serious than that.
The other annoying part is when Kirk releases his evil double, by himself, when he looks as weak as a kitten. Cue the fight and escape. It does set up a nice scene on the bridge though and reveals what Spock mentioned earlier - that Weak Kirk is not afraid, even if he has lost his drive and guts.
Excellent episode, best i've seen so far.