Season 4 was a very solid season on the whole. There are some fantastic episodes, such as "Rarity Takes Manehattan", "Pinkie Pride" and "Maud Pie". There are also disappointments, such as "Somepony to Watch Over Me", "Rainbow Falls" and "Simple Ways". Most fall in between of above average to very good, don't consider any episode of Season 4 bad actually and consider its lesser episodes better than the lesser episodes of most of the show's seasons.
The first part of Season 4's two part finale "Twilight's Kingdom" to me is brilliant and one of the best of the season. 'My Little Pony: Friendship is Magic' was on the most part very successful with its two parters that occurred at the beginning and end of nearly every season, even with some misgivings. A strong contender for the best two parter of the show is to me "Twilight's Kingdom", which was outstanding in pretty much every way.
Admittedly there are the not so great and at points rather ugly rainbow designs, but the good things are so many and so brilliant executed in a way not seen as strongly as with the previous two parters that a big part of me was willing to let that go. The rest of the animation is fine, the vibrancy of the colours is still intact, as is the vivid atmosphere and the meticulously detailed backgrounds. The character designs became more polished with each season and one can see the growth here. The music is dynamic with the action and has an infectious groove and atmosphere.
In my view the writing is some of the best of the season. Not just because it is well written, even in any re-capping it doesn't get bogged down too much by exposition or over-explanation, but also because of its emotional complexity. There is some heart-pounding and tense conflict (betrayal was seldom this wrenching the gut in the way it is here in this two parter). As well as emotional moments that really tug at the heart-strings, that were even stronger in Part 2, and Discord brings some great comic timing that balances beautifully.
Likewise, the story is tense, poignant and a lot of fun. Even in a part that is basically setting things up, it is eventful stuff and always arresting. One may worry that with more than one conflict going on that the episode could risk being over-stuffed and muddled but it was neither. All the characters are true to character and interest in their own way. Twilight is regal and relatable and Discord never stops being a joy. Tirek is one of the show's better villains in my view, he's got a genuinely sinister vibe, motivations aren't confused and it feels like things are at stake. He is not one of the missed opportunity villains like King Sombra was.
Cannot fault the voice acting, Andrea Libman is truly heartfelt and John DeLancie is formidable and hilarious. Mark Acheson is suitably sinister as Tirek. Tara Strong also gives emotive voice acting, loved her voice work when Twilight was interacting with Spike.
Overall, brilliant. 10/10
