“Our Hero, Balthazar” is not really an elevator-pitch kind of movie. Sure, there’s a log-line: A wealthy New York City teenager ( Jaeden Martell ) who, in a misguided attempt to impress a girl, travels to Texas to try to stop a school shooting. But it’s the describing of it that gets tricky: It’s a black comedy, but also sometimes just a comedy. It’s a thriller and a satire. It’s a commentary on performative activism, gun culture and toxic masculinity. Mostly, it’s just an entertaining ride. Owen Gleiberman, writing for Variety , called it “a cutting, audacious, and at times astonishing movie.” Perhaps it makes more sense to understand that “Our Hero, Balthazar,” which is currently in theaters, comes from a filmmaker known for his collaborations with the Safdie brothers.…