It was entertaining, intriguing (or maybe suspenseful), had a terrific build up and a very nice (and I'm thinking simple but I suspect that is left up to the individual viewer) character change. I am not a critic, just a film fan, but I thought it was great. I was appropriately..er..uncomfortable and laughing at the same time. I liked the main character and even found myself rooting for her.
Technically, I thought it was a beautiful film as well: the setting, the camera angles, unspoken messages and the small actions to build the depth of the characters. I felt like I was a friend hanging out with them the whole time.