As of this writing, 'Twilight's Kingdom' is the most recent episode of My Little Pony: Friendship is Magic. This is my second ever time watching the episode. It is still the greatest episode of the show up to this point.
Alright, first thing's first. Twilight's internal conflict, about finding her place as a princess, works best on a meta level. It sets up a contrast between what Twilight HAS been for the past four seasons, and what she may change into now that she's a princess. Season 4 largely ignored her new status until the final stretch of episodes, where she seems distinctly uncomfortable with her status. That carries over to this episode, which is largely based around that. A lot of what happens in this episode points to big changes in the next season, which is represented partially as Twilight's role as an alicorn. This is in conflict with At its best, 'Twilight's Kingdom' presented it as "why am I here if I don't do anything? Can I go home yet?"
However, unfortunately, at times the dialogue lacks that nuance, making it seem like Twilight simply feels worthless for reasons that aren't entirely stated. This is frustrating, because it ignores Twilght's previous sense of purpose. Thankfully, these moments are few and brief, keeping it from being a major issue. Most likely it's not the result of bad ideas like 'Magical Mystery Cure', but simply flawed execution, which is much more forgivable as the main idea does usually come through.
Next, let's talk 'You'll Play Your Part'. This song has been highly beloved since the episode, and some have compared it to 'This Day Aria'. In the times I've listened to it, though, it's one of my less liked songs of the season. Sure, its strong points are blissful, but its less bombastic moments fall flat for me. Maybe next time it'll hit the mark.
One moment, after Tirek's appearance, Celestia introduces him by explaining lore in a storybook format. This is reminiscent of the opening of the pilot, which hits home to me as that storybook opening was one of the things that got me into the show in the first place. It's a callback to the start, and a partial reminder of what I love about this show. The constant presence of little bits of lore adds to the show, making it more meaty than our average cartoon. It's a little element of fantasy that fleshes out the world, and makes the setting compelling.
One thing that season 4 introduced was something of a running plot. Several episodes were connected by common themes and events that led up to the finale, and many of these were the season's best episodes. I've discussed these themes enough, but it felt nice when the show confirmed almost exactly everything I'd been writing about over the course of the season. The first season actually had a running arc first, with the mane six visibly forming bonds, but season 4 reintroduces it, albeit on a lesser scale. That lesser scale proved itself something of a problem, because it made every other episode feel like filler, especially considering how hard good character development was to come by in S4.
One thing that sets the season premiers and finales apart is their incredibly good visuals, and 'Twilight's Kingdom' surpasses even 'The Crystal Empire' for visual brilliance. Scenes are more detailed than ever before, and are filled with really aesthetically pleasing ideas. Of note is the energy ball that the princesses create from their magic, a particularly flashy design, and one of the episode's flashiest. There's also the fight scene that this episode is most well known for, which seems to take influence from Dragon Ball Z of all things.
The second half begins with Twilight taking in all the princess' magic to hide it from Tirek. This plan requires her not to tell her friends, lest they give her away. Except, this whole plan amounts to nothing. Twilight telling her friends about everything might actually have protected them, and Tirek would have known she was a princess anyways because of the stained glass window. Oops. I think this nicely establishes that the princesses aren't infallible, but having it be unravelled by such a small, minuscule oversight isn't particularly satisfying. At the same time, it further establishes Tirek's menace, if only through rudimentary use of the Worf Effect trope.
Perhaps the best part of the episode, however, is how it establishes Twilight's friends as actually mattering. In my review of 'Magical Mystery Cure', I pointed out how that episode minimizes the importance of the other five main characters despite the show having, at that point, effectively gained an ensemble cast. A later scene in Part 2 has Twilight decide that no, her friends do matter. Indeed, this turned out to be a smart move. Twilight had no idea if Tirek would keep his word, and ultimately it did work out in the end.
In fact, with the show revolving around friendship, it only makes sense that that'd be what defeated Tirek. The main six showed their character growth and represented their elements throughout key episodes of the season, and it'd only make sense that it'd be how Tirek was defeated. Besides, Tirek didn't know about the box, and Twilight did.
All six of the main characters have at this point begun to plateau in character development, and their six "key" episodes throughout the season established these plateaus. 'Twilight's Kingdom' is as much a culmination of the characters' development as 'The Best Night Ever' was one of their friendship. However, after 'The Best Night Ever', the writers moved on to developing the characters more differently. What'll happen next remains to be seen, but it definitely needs to be something new.
Speaking of sticking it to 'Magical Mystery Cure', one of the episode's best lines is also one of the final ones. "But what is the Princess of Friendship without her friends?" Celestia asks, rhetorically. This is the polar opposite of the S3 finale focusing entirely on Twilight's development. Where 'Magical Mystery Cure' gave Twilight all the credit, 'Twilight's Kingdom' spreads the credit around. It's ambiguous what exactly this means for Twilight's friends, but at the very least they've gained a higher status, which by the show's own logic they deserve. It's also a nice touch that Spike gets a mini-throne.
Installing Twilight and her friends in a castle sets up the show to potentially move in a new direction, which is something the show sorely needs at this point. The usual formula and limitations of MLP are reaching their breaking point, and the only way for My Little Pony to move forward now is for it to break the mold in the fifth season. With that coming up, it's very possible that they just may do that. We'll see when it comes, but in any case, I think I'm ready for it.