Isn't it great when your crazy villain is probably the worst part of your episode? In a season of ups and downs, this episode ended it on a high note for me. The idea of "What would have happened if X never occurred" has been floated around the fandom for years now, and it was interesting to see a canon vision. It was also interesting to see a full scale Equestrian war. I think Sombra's alternate reality was my favorite, so it sucks that they blew that first, but none of them were bad persay... Except maybe Discord's, but it was so short, whatever. I think Twilight and Spike were fun, the visuals of the time travel and the fighting were great. It was a well timed and well executed episode.
And now we get to the elephant in the room. Starlight Glimmer. I will start by saying that her insanity, and the way it visually and strategically played out was fantastic. Her plot was so beyond the realm of reason, that you couldn't help but be impressed by it. Also, can we address that she is the only other pony to crack a Starswirl spell, AND she can fly using magic? Fuckin' Zaheer up in this house. No, all of that was great. It was her backstory that didn't really hit home. That whole thing with her friend was a fine instigator, but there were a few dozen levels of psychotic deterioration between "I lost my childhood friend and have a childish reason for it," to "I'm going to build a hamlet where everyone gets their cutie mark taken away," to "Fuck time and space, I'm going to wreck this person's life forever." I know there would have been a LOT to address if they had gone through each beat, but the instigating event, in my opinion, was not strong enough to justify bringing about multiple end-of-the-world scenarios for the sake of some vengeance. Again, that isn't to say that Starlight wasn't a ton of fun to watch.
All in all, a great end to a pretty good season. For those of you familiar with how this works, there is one more image left to do. Finals are in full swing here, so it might take time to get to. But I do hope you look forward to it.
MLP:FiM is (c) Hasbro