I don't intend to review all the new MLP episodes, but since I posted a comment in broniesaremagic about it, anyway, I thought I might as well repost it here. Keep in mind that this contains spoilers, obviously.
Enjoyable episode. :) It felt less rushed, with a bit more time for an exposition etc. — although I still think 22 minutes is NOT a lot if you want to tell a proper story.
The idea with the mirror pool that you actually step into and emerge from again on the other side where you're already waiting for yourself was really neat — sort of reminded me Cocteau's Orphée, too, where the transition to the underworld was done with a liquid portal (filmed using liquid mercury, no less).
Pinkie making a "crazy" face that turned out to be a G3 pony was hilarious. ^^ And the orange frog was cute, too — hope Twilight got around to changing him back. :)
It was also nice (well, you know what I mean) to see Pinkie – the real Pinkie! – sad and dejected for a change, especially since she wasn't going all the way into Pinkamena-style crazy. As she said herself in the past, it's true, some days are dark and lonely; and sometimes, Pinkie being there to show you that it isn't that bad can actually be a bane rather than a boon, it seems.
I wonder what's up with the secret compartment in the library, too. (Given what happened, I'm not so surprised the book was hidden, though.)
The only thing I didn't like was the "someone says something mildly funny and everyone laughs as the screen fades" ending. I REALLY hope that's not going to be standard from now on; it's clichéd and trite and almost invariably entirely forced.
EDIT: and having read [ungulata's] own thoughts, yes, I agree that it was awfully nice to see a friendship report again.
But for now, I should call it a day and go to bed. Oh, here's a joke:
Q: What do ponies do when they're really tired?
A: They hit the hay.
...yeah, it's the kind of thing that pops into my mind when I'm really tired. :P