Coldplay at the United Center

Even after several million albums sold, British art-rockers Coldplay are still conflicted about their status as an arena act, and that’s one of their most endearing traits.

On the one hand, frontman Chris Martin and his bandmates do everything they can to maximize the big rock spectacle, the grand theatrical gesture and the musical bombast.

Wednesday, during the first of a two-night stand at the United Center, the musicians came out dressed in pseudo-Napoleonic uniforms and began to perform in front of a giant backdrop of Delacroix’s French Revolutionary painting, “Liberty Leads the People,” which happens to be the cover of their new album, “Viva La Vida.”

Several big globes hung from the ceiling and flashed video images of the band as it played; at times, the group deployed more lasers than any band since Genesis, and during the song “Lovers in Japan,” a seemingly endless rain of colorful paper butterflies fell on the crowd.

On the other hand, Martin has never been afraid to let his inner geek show: He’s the anti-Bono, dancing like an awkward little urchin instead of striking cool larger-than-life poses, and never hesitant to do his Schroeder routine at his black upright piano.

Throughout the 90-minute set, the bandleader frequently thanked the fans for their support, sounding genuinely surprised at his own success. And he, guitarist Jonny Buckland, bassist Guy Berryman and drummer Will Champion did everything they could to get up close and personal, running to the end of the platform on stage right, performing two songs at the end of the platform on stage left and eventually hopping down from the stage altogether to briefly perform acoustically in the midst of the fans in the first tier off the floor.

None of this made the show as intimate as the one the group played at Metro to celebrate the release of its last album, “X&Y.” But it felt as special as any party for 20,000 can, and the good will the band created extended to the audience indulging two renditions of the new song “Lost” for the benefit of a video filming, as well as the heavy sampling of the more arty, less anthemic songs from “Viva La Vida” sprinkled between guaranteed crowd-pleasers such as “Clocks,” “In My Place” and “Yellow.”