After glancing over the reviews, and seeing people's confusion/dissatisfaction, I almost didn't bother to watch. If one can only think linearly, or if they are uncomfortable with an unconventional movie, then this movie will probably not be enjoyable. Off the top of my head I'd call it Paranormal, but there are almost equally strong elements of Crime, and Slice of Life.
I tried doing thing whole "figure-out-the-plot-twist", don't bother.....trust me. This may also be an element of what turns people off. This is purely a story being told. Just empty your mind of any preconceived notions and watch. Everything ties in smoothly at a good pace, and the ending is satisfying. Remember, I also labeled this as a Slice of Life. This means no dramatic moments of extraordinary epiphany followed by action. In the end the MC knows exactly what's going on, and just like every human who exercises free will, makes a choice. Also, just like many of us emotion will overcome sense. His heroic deed was accomplished in an anti-heroic style, but just like in life his obsession will.......well I've gone on long enough I think.