You should definitely watch this movie. It is not necessarily good. It cannot be called quality filmmaking. However, this movie is way more entertaining than it seems. It is a shinning example of the higher echelons of bad taste. I'm not suggesting that you curl up around the fire and watch it with your mema and pepa, but a stoned night a alone is a reasonable suggestion for viewing A Christmas Horror Story.
The movie is not for everyone, but I personally appreciate the effort. As an adult, I am not the biggest fan of Christmas, yet for some reason, I really like Christmas movies. Yes, I even like many of the corny Christmas movies, especially the family-based comedies. I am the same way with football movies. I love football movies, but I do not like watching football.
I always thought all of these Christmas/horror spoof films were simply a crock of shit, a cheesy gimmick. In some ways, I was wrong. While all of that is true of A Christmas Horror Story, it is the kind of crock-of-shit-cheesy-gimmick movie I like every so often. I guess, I just enjoy Santa throwing an elf out a window while being called a "cocksucker." That is one of many amazing things that happens throughout this movie, and you might enjoy this type of entertainment too.