I guess I'll be in the minority for the whole "alicorn" thing. I grew up with the actual meaning of the word. Never liked how it's misused here or in the general fandom.
Still, a great episode that oozes nods to the fandom. It's great to see a product that isn't just name-dropping, that proves the production team acknowledge a lot of what's gone before. This is one of the few episodes that directly follows on an earlier one, and thus grows many characters and the series as a whole. Since most of the episodes are one-offs with no particular consequences, this more arc-oriented story will surely be a fan-fave once all is said and done.