Occurred to me I'd never even seen the episode, so I'm watching it now (roughly halfway).
First thoughts:
- So these children are 300 years old, apparently don't work, but still have food, and their clothes look OK (a bit shabby, but not worn out, even after 300 years of wear). I'd want a set of those, too.
- Do we ever get an explanation as why this literally is "earth 2"? (even down to the same continent shapes?)
Other than that, not too bad up till now. Certainly not stellar Trek, but reasonably entertaining.
EDIT: ok, so they do touch the food problem in the 2nd half. Still, mighty impressive that the food they had lasted them for 300 years (and didn't spoil).
Also, the Kirk - Miri interaction could be interpreted as a bit creepy but I'll buy such overtones weren't intended in the 60's.