He Knows is a horror film about Sammy the Elf punishing those on his naughty list. Young Christina witnesses her father and brother being murder by Sammy the Elf.
Years later Sammy the Elf returns and he is killing off old friends of hers. The movie itself isn't bad, but it could use a bit of trimming. 100 minutes is a bit long for this sort of thing. 75 - 85 minutes is closer to an ideal run time for a picture like this.
There are some pretty good kills. Character wise, I'm not sure that there too many likeable characters in the film.
The film is shot well, and the special effects are pretty good. I did notice one continuity issue with Jessa Flux's character. Her hair has some pink in it. Then at one point there is no pink. Just a minor issue, but noticeable.
Most of the cast is unfamiliar to me except for Lynn Lowry (Sugar Cookies, Shivers), Jason Crowe (Space Babes from Outer Space, Don't F in the Woods) and Jessa Flux (Murdercise, Debbie Does Demons).
I guess your enjoyment depends on how much you like these type of movies, or if you're a fan of any of the cast.
There is a post credits scene in this.