Writer-director David Ayer made his name showing film lovers the ugly, dangerous side of Los Angeles, and his greatest achievement to date is “End of Watch.”  The documentary-style film focuses on two police officers working the roughest parts of L.A. Brian Taylor (Jake Gyllenhaal) is an ambitious former Marine who films many of his on-duty adventures for a night-school project. His partner, Miguel Zavala (Michael Pena), is a devoted father and husband expecting his second child.