ELEPHANT reminded me of UNITED 93, in terms of how raw and direct it was in portraying the horrors of that day.
It cleverly captured that mundane feeling of a normal school day, Gus Van Sant deliberately cast actors to do their own thing in the movie (not following a script, they used their individual talents to make their characters unique so that you'd empathize with them in the event of the shooting).
Camera angles were used to pinpoint everyday typical moments where a person can walk down the hall, observing their crush, not realizing what's about to happen that will change their lives forever.
I thought it did a superb job of building up the suspense to the movie's recreation of the COLUMBINE tragedy.