I like to use plenty of pictures in my episode commentaries if nobody minds.
I loved episode 1. I don't know why it doesn't have a better reputation. The opening was a great way to start both the episode itself and the show as a whole. It certainly sucked me right in. Note to writers: beginning your show by introducing an epic conflict is an easy way to get my attention.
The introduction of Twilight and Spike worked pretty well. I love the ominous mood that sets in right in this scene. Nightmare Moon is coming, and there's nothing that can be done to stop it. The sand is running out.

Twilight's attitude about going to Ponyville to make Friends is hilarious in hindsight given how similar many new fans felt about being asked to watch the episode. It's like this show was destined to amass this unlikely fandom. Skeptical newcomers can instantly relate with Twilight, which draws them in further. Before they know it, they'll find themselves caring about what happens next.
I already knew who the characters were when I watched the episode for the first time, so when I saw that the first pony Twilight met was going to be Pinkie Pie, I knew that was pretty much the worst case scenario. This was bound to end badly, and it did.
Ah Applejack. I don't have much to say about that scene. As usual, Applejack has a hard time standing out as her big scene was immediately overshadowed.
Rainbow Dash gets a very interesting entrance. She immediately stands out as a very colorful character, and not at all what most of us expected of a rainbow colored pony.
Ah Rarity. Who could have guessed from this introduction that she would become so popular? I didn't. This scene did no justice to the many layers she has to her personality, which is actually a good thing if you ask me. Characters should be introduced, not explained in their entirety all at once.
Fluttershy is instantly adorable, and just gets more adorable as the scene (and show) goes on.
Pinkie Pie finally gets a proper introduction, and drives Twilight to drink. And look, Derpy makes her first appearance.

And the ominous mood returns. I love it. Twilight knows disaster is about to strike and time s running out to do anything about it. She does manage to stay unusually calm given the circumstances, but it's clear that she's scared, perhaps more scared than she's ever been in her life.
And then we get the cliffhanger. Again, in hindsight it's amazing how well this episode works for skeptical first-time viewers. It's a show about technicolor ponies, and the episode ends with the apocalyptic return of a bitter goddess. Our hero failed to avert the disaster, the princess is in another castle, and the villain is laughing in complete victory.
Cue the happy credits music.