Derpy Cameo: She is seen in the crowd during the jousting tournament.
Rarity calls Spike "Spikey-Wikey" for the third time in this episode. The other two times she called him that were in the episodes, "Secret of my Excess" and "Dragon Quest."
We are shown both Twilight and Spike's worst fears in this episode when they look through King Sombra's door. Twilight's worst fear is failing Princess Celestia, while Spike's worst fear is Twilight sending him away.
Fluttershy's ears briefly disappear after Rainbow Dash says that she "might go easy on her," and they reappear when she jumps off the hay stack.
Rarity: I am running out of weathering materials for the traditional crafts book. I've just made a hat out of three pieces of hay and a drinking straw. I made it work, but still...
Twilgiht : I passed!
Rarity: (Singing the Success Song)
You were prepared to do your best
Had what it takes to pass the test
All those doubts you can dismiss
Turns out you were
Everyone : Prepared for this!
Applejack: You clearly have just what it takes.
Pinkie Pie: To pass a test with such high stakes.
Fluttershy: We knew for sure you would prevail.
Rainbow Dash: Since when does Twilight Sparkle ever fail?
Everyone: All those doubts that you can dismiss
Trust yourself and you cannot miss
Applejack, Pinkie Pie and Rarity: Turns out you were
Twilight : Turns out I was
Rainbow Dash, Fluttershy and Spike: Turns out you were
Twilight: Turns out I was
Rarity: Turns out you were
Everyone: Prepared for this!
Spike: (Chuckles) Yeah, I knew everything was going to be fine.
Fluttershy: Isn't there somepony else who could take over the jousting demonstration with you?
Rainbow Dash: The fate of an entire empire rests on us showing these ponies a good time. But, y'know, if that isn't important to you. (Fluttershy starts crying) Okay, okay, I'll take it easy on you next time. But not too easy. I've got a reputation to maintain.
Rainbow Dash: Who wants a flugelhorn?
Pinkie Pie: I want a flugelhorn.
Rainbow Dash: Who else wants a flugelhorn?
Pinkie Pie: (Angry) I want a flugelhorn!
Rarity: (After being a crystal pony) I do so wish it was permanent. Did you see how my mane just absolutely sparkled?
Applejack: But good things are better when they're a rarity.
Shining Armor: (to Twilight) You've gotta stop saving my rump like this. It's starting to get embarrassing.
Spike: (After looking through King Sombra's fear door) We were home. You told me you didn't need me anymore. You were sending me away.
Twilight: (Hugs Spike) A fear that will never come to pass. I'm never going to send you away,
Jim Miller, who provides the voice of King Sombra, also works as one of the head storyboard artists for this show.
Friendship Report: Twilight learned the meaning of self-sacrifice.
This episode revolves around Twilight.
The Crystal Empire bears a strong resemblance, in both design and layout, to the title city from the show Stargate: Atlantis.