I was really excited for an episode centered on multiverse theory. I thought for sure, once that happened, it would help to clear up any possible paradoxes in future episodes regarding time travel. Instead, the alternative universe was a universe composed of antimatter.
Season 1
The Alternative Factor: Disappointed, Table of Me
Errand of Mercy: Klingons Shmingons
The fortress was obviously built of the same stuff as the fortress from the original pilot. Cool.
Devil in The Dark: A Little Girl Talk Goes A Long Way
As soon as the miner showed them that silicon sphere I knew it would end up being an egg and the source of their trouble with the man-incinerating native.
This Side of Paradise: Paradise Left
Spores are making everyone emotional — starting with Spock! He’s smiling. He’s just hanging out. He’s kissing the pretty blonde (an honor usually bestowed on the captain). What could possibly go wrong?
A Taste of Armageddon: War, What is it Good For?
Fighting war virtually? Awesome. Disintegrating your own people? Not cool. The fact that this so-called civilization has managed to go half a millennia doing just that — rather than have peace talks — is crazy dumb. That’s why Spock, as understanding of their logic as he is, did not actually approve.