Disturbing
After watching this film, I cannot give it a perfect score, nor can I give it a zero. In fact, to place a rating on something that transcends almost all flash animation I've seen is virtually unjustifiable. Nevertheless, I will try.
Your graphics were good, but sketchy and styles clashed at times-- in the parking lot, for example. Sound was low quality but I liked the music selection.
But everyone with half a heart will draw their opinion from the subject matter. Personally, I found the animation disturbing with too much empathy forced on the characters and an apparent effort to make their crusade admirable. Lines like, "Shootin' people," and "Heh, natural selection," were severely misplaced even though they might be accurate to the real events. The animation simultaneously portrays the two as both victims and moderately popular students. Christian being assaulted in the bathroom draws sympathy while the friendly "hellos" the pair get from their friends even as they go on their rampage is just eerie.
This may be fair, however. It would be wrong to completely dehumanize them just as it is wrong to laud them. Though it's not comforting to think of, they were human beings.
The animation seems to crawl along once the massacre starts. Where are the students scrambling for shelter? Where is the principal telling people over the PA system that the school is in lockdown? There are obvious constraints on both the artist's patience and the ability to process graphics information, but as it is, the serenity of the massacre is awkward beyond reason.
You've probably seen Michael Moore's "Bowling for Columbine" but I'm actually reminded of "Fahrenheit 9/11". In "Fahrenheit 9/11", Moore chose not to show any footage of the twin towers because he felt the audience had seen the terrorist act fifty times over. Instead, he played audio of the scene in New York as events unfolded and let it reinforce the viewer's own graphical and emotional interpretation of the September 11th. While it may not be fair to copy Moore's style, I feel that a similar approach would have been infinitely more compelling.
Though there were some things I decidedly didn't like, I hesitate from judging this too harshly based on things that made me uncomfortable. All great art is controversial at first and yours, if nothing else, is controversial.