Marvel has mastered the PG-13 action movie. Its films are accessible to both kids and their parents, with the latter then forced to buy toys for the former immediately after the closing credits. Conversely, why did "Amazing Spider-Man 2" fall so flat that it forced Sony's return to the drawing board for yet another reboot? The filmmakers killed off Emma Stone's Gwen Stacy just ten minutes before the end. Yes, that is based on a classic 1973 comic storyline, but this is a superhero flick, not "Ordinary People."