Held back by its need to aim for a teen audience: ultimately too tame...

...to do its grim premise justice. The concept for this film was fantastic, but it didn't dare to aim for an adult audience and desperately wanted to be a summer blockbuster for teenagers. It's still a decent flick, but I feel it would have worked so much better as an R-rated science fiction film.

http://www.the-fanboy-perspective.com/a-rant-against-modern-tentpole-film-making.html