With the atrocity of the Columbine massacre still fresh in many American minds, Gus Van Sant has a go here at imagining some of the psychological and societal causes that drove two ostensibly ordinary college lads to arm themselves to the hilt and take to the corridors of their school with devastating effects. "Alex" (Alex Frost) and "Eric" (Eric Deulen) are unremarkable in almost every aspect of their teenage,…