Matthew Bausone and Eric Folks play teenage Columbine shooters in a production of "columbinus" at Paramount/Emerson Black Box theater.

Since one of the most highly publicized mass school shooting, 14 years ago, at Colorado’s Columbine High School, Americans have been reminded time and again—most recently last week at Navy Yard—of the shift towards high casualty counts in American murders. The playbill of the American Theater Company’s performance of “columbinus”—a show exploring the mass shooting that took place in the Colorado high school in 1999—included a map of all school shootings in the U.S. since Columbine, the shockingly numerous dots like bullet holes through the country. Despite sometimes jarring stylistic shifts, “columbinus,” playing at the Emerson/Paramount Black Box theater until Saturday,  presents an emotionally honest and consistently engaging response to a tragic event, thanks to an often-brilliant conceptual script and emotional, generous performances by the two leads.

Writers P.J. Paparelli, who also directed the production, and Stephen Karam gave each act startlingly different stylistic ground, each beautiful and unique. The scenes moved from one to the next fluidly, and with the exception of the haphazard final act, were all deliberate and artistically pleasing. The first act was an examination of bullying and social pressures in high school largely devoid of gun violence in which actors play high-school archetypes. Strikingly distant late-1990s fashion, music, and slang pervade each vignette. Many moments, including a gorgeous scene in which actors pick totems representative of their respective stereotypes from suspended, backlit slabs to Gary Jules’s version of “Mad World,” are breathtaking. Other scenes, especially a prolonged interpolation of the “Romeo and Juliet” balcony scene between the “Freak” and the “Druggie,” seem more like slightly classier, R-rated versions of Degrassi.

Despite the sometimes cliché content, the first act never drags, as a result of the fascinating performances by Freak (Matthew Bausone) and Loner (Eric Folks). Initially sympathetic, Freak, whose laconic cadence and pent-up artistic passion evoke a young Jeff Bridges, and Loner, a frenetic hot temper, fall ever further into thoughts of revenge against their popular tormentors. By the middle of the act, it becomes apparent that, in contrast to the intentionally two-note performances of their archetypal cohorts, Bausone and Folks are embracing deep subtlety in their characters. Especially compelling is Loner’s attempt to ask the Christian girl, Faith (Leah Raidt), to prom. Alternately charming and brutal in his flirtation, Folks perfectly captures the swings of his character’s anti-social personality. After the eventual rejection by Faith, Loner unleashes a sexually violent tirade full of shockingly kinetic rage.

Paparelli and Karam elegantly write the anonymous characters to take on identities by the end of the act. Loner and Freak start making pipe bombs, communicating angrily over IM, and openly discussing killing their bullies and others at the school. Despite the namelessness of the characters, it becomes increasingly apparent that they the two aren’t just Loner and Freak, but rather Columbine shooters Dylan Klebold and Eric Harris. Such a device works brilliantly at stopping initial prejudice against the duo. For much of the act, their grievances and anger seem overblown, but by no means psychotic, and their moments of discourse and friendship are enough to make them somewhat endearing. Thus, it is horrifying when they embrace truly homicidal mentalities in a series of highly surrealist scenes including an “Anarchist Cookbook” bomb-making show.

Surrealism and superfluity vanish at the outset of act two. A largely verbatim documentation of the few nights preceding the killing and the massacre itself, the act uses 911 records and home videos by the killers to construct a realistic retelling. Avoiding the sensationalism that they slip into at points in the first half, Paparelli and Karam stage the shooting tastefully. Klebold and Harris tote their weapons and stalk the library, but instead of actually shooting, they indicate murders by slapping the blackboard at the back of the room. The victims and hostages describe their actions in the past tense while sitting on chairs and lying under tables in the library where the killers carried out much of their carnage. The authenticity and leanness of the act maximize emotional impact. After Klebold and Harris shoot themselves in the head and the lights come up, the entire theater is silent for several minutes.

The last act is disappointing compared with the rest of the show. Each actor, excepting the shooters, plays several roles, and besides an astonishing cross-dressing portrayal of a victim’s aunt by standout first-act Jock (Jerry MacKinnon), there is too much character saturation. Despite the failure of the act, the overall punch of the play remains, with the names and faces of the victims projected onto the back wall of the stage at the show’s conclusion.

Given the sensitive nature of the material, it is particularly bold for a theater production to attempt to show Columbine’s violent scenes, but because of tasteful decisions on the part of the playwrights and the unavoidable confrontation with evil that “columbinus” affords, the production certainly qualifies as a riveting night.