This reminds me of "A Clockwork Orange"...
...What I mean is, you try and get into the head of those two children in order to show us that, despite the fact that they were cold-blooded murderers, they believed that they were correct in their actions, and you did it in such a way as to make people believe that they were, in a way, correct. Now, I definitely don't condone murder, but you can't say you didn't at least feel an iota of sympathy for the two bastards. It's like Uriah said, something obviously hurt these children in such a way as to make them destroy those who they believed had wronged them.
Anyway, I love Flash movies which actually inform us of what's happening around us, or rather remind us that this stuff happens every day. It allows us to immerse ourselves in the violence, so that we may see the error of our ways-- so we can see that this BS is wrong. I think it's about damn time somebody did a Flash about Columbine. Excellnt animation. I like your style (but Pencil still pwns Paint Brush!), I loved how everything was so fluid and so emotional. You really helped show us how each of us has our inner demons, and extreme hatred. Much love, brah.