NB! I am changing my marking system, so that now grammar has lesser weight. The maximums are now 20/30/40/10 in corresponding categories.

«A Hairy's Hearth’s Warming»
by Pencil Melody

The short description of the fic is quite sufficient: «Nopony should be unhappy on Hearth’s Warming. Cherry Lattice, also known as Fili-second, decides to make sure of that by paying a special visit to a certain somepony.»

Grammar:
It's a short fic, with no noticeable grammar problems. 20/20

Style:
All in all, it's quite fine, but there are few eyesores, like the rather questionable choice of epithets for descriptions of utterly innocent things, such as "genocide" of sweets, or "strangulation" for a hug), or «periwinkle-colored muzzle» that seems to go contrary to otherwise simple and even text.
The main problem is that I found the jokes in the fic to not be funny. 20/30

Plot and Characters:
Are questionable, and the question is mostly "Why?"
Why move the action to the Power Pony universe, if the main protagonist is clearly still Pinkie Pie, whatever name you give her, and all the events could just as well take place in Poniville or Canterlot with minimal adjustment?
Since all the plot of the fic is aptly summarized by the description, there is little need to go into more details regarding it.
By itself, though, the characterisation is quite good, and with a limited word count, the protagonist meets a lot of OCs, each one of them, while only given in very broad strokes, is written well enough for the chosen format.
That being said, due to banality of the events and unnecessary overcomplication of the setting, there is no expected warm fuzzies of a fluffy fic, which was, as far as I can see, the main goal of the fic.
20/40

Personal Preference:
Eh. Slice of life and random fics are not exactly my favorites, and this one was not a great example of either, especially since the humour was not to my liking and I failed to get the aforementioned warm fuzzies. 2/10

Total Tally:
If it was indeed the first story by the author, then it is a rather commendable job. I would recommend to concentrate more on the plot, and add some heft and consequence to the character's actions. There is a very solid foundation in this fic - good grammar, style and characters, so now it's just the matter of using it all to maximum effect.
62/100