Bruno Mars treated fans to an intimate concert at Cunard Hall on Thursday. The event allowed in 300 fans, plus VIPs including “Trance” star Rosario Dawson, singer Jason Derulo, “30 Rock” babe Katrina Bowden and Vincent Piazza of “Boardwalk Empire.” Rev Run and DJ Ruckus got the crowd going with a 45-minute set before Mars sang hits including “Locked Out of Heaven.” The concert feted the arrival of the Galaxy S4, and the kickoff of Samsung Experience Stores at Best Buy locations.