I would consider this psychological horror rather than thriller and I think it works quite well in this respect. I am now more afraid of the human psyche and I know for sure that I would never want to be a psychologist. However it is very repetitious in the first half and so it gets boring very quickly. Also there is not much going on visually in style, colors, shots, camera movement, etc. Overall I think it does a good job within its obviously small budget.