Another fun episode. And a very fast-paced and action-filled one at that, nicely complementing the previous high-drama and slice-of-life episodes.
I mostly managed to avoid spoilers: the only things I knew about before watching it was that it had to do with Daring Do (fairly evident from the title), and that Daring Do in fact turned out to be a real pony, not just a character from a series of adventure novels. Certainly an interesting plot twist.
More interestingly, Ahuizotl's real, too, and none of the Mane Six so much as batted an eye at that. Well, I suppose that in a world inhabitated by timber wolves, crag-adiles, bog monsters, manticores, cockatrices, fabulous sea serpents and Cerberus himself, another critter is business as usual. :)
There was continuity, which was nice to see; Dashie's not the only fan of Daring Do, Twily also is. Indeed, as Twilight recalls, she was the one who introduced Rainbow to the books in the first place. And speaking of the books, I was quite amused by the notion of Daring Do being the author of her own novels. And under the name of A. K. Yearling, even — hmm, I really wonder who she's based on! :P (It makes you wonder, too — which name's real, and which one's a pseudonym?)
Regarding references and parodies, was Dr. Caballeron (the guy who stole the ring) based on René Emile Belloq? I couldn't say – it's been too long since I watched any of the Indy movies –, but I'd not be surprised.
The episode had a surprising amount of (cartoon) violence, didn't it? Daring Do beating up Ahuizotl's cat minions (and apparently giving the kitten a black eye!), for instance, and Ahuizotl almost feeding Daring Do to the piranhas. I wouldn't have expected that in a series aimed at six-year old girls, but then life's taught me that six-year old girls should not be underestimated.
There were a variety of interesting expressions again. Twilight exhibited one recalling her "Read!" poster early on, and of course Dash had another "why wub woo" moment — almost. Indeed, Dashie was highly adorable, especially early on in the episode when she was all excited about the new book — and at the very end, when she got it a week before everyone else and literally bounced around, brimming with glee.
Most of the other ponies – beyond Rainbow Dash and Twilight – were supporting characters at best. Fluttershy played a role in the beginning, but never got another line after they met Daring; Rarity and Applejack played bit parts at best. Pinkie at least got a bit of zany antics — I liked the "random holiday party" holiday, and having her paint a literal red line when they travelled — that was funny. I like jokes that unexpectedly take a metaphor or image to a literal level, and red lines on maps lend themselves well to that. (I'll note, though, that the MLP:FiM writers didn't take Hergé's advice: the Mane Six were shown travelling left.)
The episode was over very fast; it didn't feel like 22 minutes. And some things were glossed over, such as how Twilight found out A. K. Yearling's address, but then it's better to cut non-essential parts of the story and devote enough time to the essential ones than to try and cram everything into the allotted time and fail to give enough time to anything.
I did like that the episode ended with a friendship diary entry, too. I missed those friendship letters.
And Dashie spontaneously glomping Daring Do? That was the cutest thing ever.
Elsewhere: episode discussion post in broniesaremagic; EqD episode follow-up.