Have you ever read the book Influence: The Psychology of Persuasion? It's powerful and will explain why there are so many negative reviews on this great movie.
This is is above average. It is darn near excellent. The concept is unique. The acting is great considered it is mainly a two actor show. It will leave you thinking, thinking about the future, thinking about man-woman interaction, and would make you think "what would I have done?" I rate this as a must-watch.