As a big fan of cosmic horror, this didn't really deliver for me. It did nothing really new nor unique and none of the characters really mattered in anyway. Why was she a writer? What is the danger of this being apart from the apparent mind control? Why were her friends under the control and just show up while it is implied that the house should be empty?
As a former competitive martial artist myself I have to say this looked more like a onehanded brawl than a match. The rules were underexplained and there wasn't really any focus on technique or what made these two fighters great apart from maybe their conditioning. Great cinematography though!