Having read about the film for a number of years I picked up the Dark Sky DVD a few years back and thought it was terrific. I can understand why people find the opening montage a little overlong, but it serves a purpose in that there's a payoff in the way the movie unfolds. It's a shocking montage, no doubt about it, but as I said, it serves a purpose.
Anyway, I love the film and think it's one of the better efforts to emerge from Spain during this period. Could I kill a child? I could kill some of the chav vermin that live near me, for sure - but they're feral, they're not even strictly human.