It was genuinely amusing to see Kinnaman jogging down the street in slow motion; the bouncing reindeer nose on his sweater was a highlight. Another enjoyable moment came when he appeared exercising in worn-out gray sweatpants. Overall, I didn’t mind the exaggerated slow-motion action sequences—it seems to be the intended aesthetic—but the film really faltered with its failure to establish any plausible reason for the father's sudden transformation into a serial killer. The antagonists also lack any discernible motivation. What initially bothered me was the scene where he returns home after months of rehabilitation, visibly damaged and traumatized, only to find that his wife hasn’t removed the Christmas tree and presents meant for their deceased child. It seemed odd; while I understand she's dealing with her own trauma, it felt as though she had returned to a normal life too quickly. The situation would only be logical if she deliberately wanted to upset him, but later events suggest that wasn’t her intention. Then there's the strange choice to have virtually no dialogue throughout the film... which would almost make sense if his hearing was impaired, except it isn’t. This significant plot element doesn’t work at all and contributes to a rather tedious viewing experience; as the killing spree progresses, it actually becomes increasingly dull.

Source on TMDB