Ha ha ha, you thought you were getting off easy, didn't you Starlight? Noooo, you're going back to friendship kindergarten. Literally. You're mission, should you choose to accept it, is to make up with your best friend from kindergarten. Do you accept?
But you must!
She and Spike worked well together. Or against each other maybe. She and Sunburst... not as well. But they did a good job of foreshadowing how he would eventually save the day, with the flashbacks where he was impressing Starlight with his freaky knowledge of magic but she was humiliating him with her own overwhelming power.
Meanwhile, in the A plot, Cadance has apparently given birth to the antichrist. Only Pinkie Pie can quell her anger! None can survive her death lazors! The entire empire will fall into ruin!
Some people said that this episode proves the comics aren't canon, which is kind of an exaggeration. Yes, they didn't mention that breaking the crystal heart should have released the Umbra, but (a) they're not going to mention something from the comics out of the blue in the show, because it would just confuse people -- see the manta ray from the chapter books that confused everyone when it showed up in the comics. And (b) there are plenty of ways that the Umbra could have existed but not been a factor, starting with Celestia closing the barn door before the cows escape a second time (like she did with Discord and the elements) and ending with them not noticing that the door to their prison was open for a few hours this time -- in the comic it was a big complicated plan and they were waiting for the heart to go down so that they could escape.
(or maybe breaking the heart killed all the Umbra, like one fanfic writer suggested -- they *thought* it would let them go but it was never actually broken in the comic, and there had to be some reason Sombra didn't just smash it during his reign, right?)
Or you can just remember that the comics were only ever 'b' canon meaning they run the plots by the people who work on the show to make sure they're not violating canon when they write them, but the writers don't bother to remember or think about what's in them when writing their own stories.
This is not really about the episode at all, is it? Sorry, but I do like most of the ideas that the comics introduce and I'd rather consider as many of them canon as possible. Except for the law against using magic on cows, that's just stupid.
So, episode. Basically -- it covered two very cringe-inducing plots and managed not to make me cringe, which means it was very well done. I really did enjoy watching it. The best parts were probably Spike's fangirls and Pinkie Pie's cheery baby-sitting despite the baby being PURE EVIL.
So overall, while it doesn't make my list of all-time favorites, it was a really good episode. 3/3