Most significantly I scored 3 stars due to story line and acts. But charactor build_up was a mess. Regardless of how people could psychologically be, from film_making aspect, there were lots of WHYs left unanswered which doesn't sound professional at least 2 me. V had a film life time 2 understand why Kevin was so but what u only watch is what he is. The movie flashes back many times but 2 prove that Kevin was cruel and still is. What u r seeing in his today, existed in his childhood as well. But no clear answer for "why"!