NOTE: the main part of the review was written on September 21st after the writer, knowing full well that he'd be missing the Discovery Family airing of the episode due to Anime USA, opted to take advantage of the episode's "leak" and watch a stream of it on that date(with the additional comments section written later on to reflect the stuff that happened during the forty days between the leak and the actual air date).
As someone whose favorite member of the Mane Six is Fluttershy, I am going to brutally honest here: Scare Master is one of her weakest episodes IMO, and I feel the big issue with the episode is the way she is handled here.
The first problem is the way she is written during the first half of the episode. I understand that Fluttershy is nervous on Nightmare Night due to it being a day where ponies intentionally try to scare each other. However, at the same time, one thing that I'm very concerned about in terms of this season is that, as part of my belief that the different types of audiences are conflicting with each other (with the writers trying to appeal to each of them instead of writing something that would be liked by everyone), a number of characters are being reverted to their Season 1 selves for the sake of attracting a new generation of kid viewers. Not only does this happen to Fluttershy here, but also, the way she is written during the sequence at Sugarcube Corner "Flanderizes" her as a outright scaredy cat (to the point that she doesn't want to eat candy out of fear that it would cause her mouth to be glued shut). It also doesn't help that the writer of this episode has proven that she understands Fluttershy (as seen in It Ain't Easy Being Breezies and Make New Friends But Keep Discord) and would have known better than to go overboard with her nervousness.
While she does eventually try to have fun on Nightmare Night (and eventually spook her friends), this leads to the other issue with the episode: the resolution and moral. On one side, it does feel like its retreading elements from Filli Vanilli and Maud Pie. At the same time, whereas she does show a slow bit of growth in Filli Vanilli, here, it feels as if Fluttershy either doesn't get any growth at all or simply reverts back to her current self after spending most of the episode as her "Season 1" self. This makes me wonder if the writers are having a hard time trying to write for her (with them relying too much on her "shy" side and not taking full advantage of the "quick reaction" jokes that she tends to excel at).
All in all, this isn't the type of episode that I need to worry about missing just because I'm busy attending a convention.
Additional Notes:
-Either the animators realized ahead of time the possibility of this episode being held back until Halloween (i.e. after Crusaders of the Lost Mark aired) or they had a lot of luck with them, because the idea of the Cutie Mark Crusaders wearing full body Nightmare Night outfits helps the episode get over the biggest issue with the episode airing out of production order: the CMC finally getting their Cutie Marks a few weeks ago.
-The pony dressed up as Jem is a way better version of her than the crap that Jason Blum gave us this past week.
-Nice to see that someone on the animation staff is a fan of, among other anime titles, Revolutionary Girl Utena. Also, as I mentioned on the thread talking about this week's episode of Gravity Falls, it's interesting to see all these American cartoons having anime/Japanese references this week (the "anime" cut-outs here; the Godzilla parody on The Simpsons; the "anime bubble" on Gravity Falls; the "Tweek x Craig" shounen ai fan art on South Park).
To round out the review,
here's some fan art I saw last night that depicts the Mane Six as various "new classics" horror movie icons.