The only reason this movie keeps you guessing is through the use of deceptive editing. Had the director used a straight-forward timeline, the "mystery" would be immediately evident.. I personally don't like contrived confusion. If the screenplay isn't clever enough to engage the movie-goer then throw in a few "cuts," jump the time-line around, and "voila" instant confusion. Much the same effect as Quentin Tarantino uses. When the movie ended, I felt cheated because the mystery is so profoundly mudane. Give me Hitchcock any day.