Samuel Aquila, the Roman Catholic archbishop of Denver, concluded the ceremony with a prayer for the dead and the living.
"All of us in some small way suffered in your suffering," Aquila told the crowd. "The way of peace means rejecting the violence of that night."
"Let us abandon the violence we consume in the media, and the violence we may harbor in our hearts," said Aquila, who penned an opinion article, published in The Denver Post on Thursday, criticizing violence in the mass media.
Cinemark planned to offer free movies at the multiplex to the public over the weekend, then permanently reopen it Jan. 25.
Vanessa Ayala is a cousin of Jonathan Blunk, a 26-year-old Navy veteran and father of two who was killed. Ayala said she believed the multiplex should have been torn down and, perhaps, turned into a park. At the very least, she said, the auditorium where the shooting occurred should have become a memorial.
"It's not about letting the gunman win," Ayala said. "He's already lost. He's lost everything he's going to be. He's a moron."
The decision to reopen even divided at least one victim's family.
Tom Sullivan, whose son, Alex, was killed, attended the event.
"The community wants the theater back and by God, it's back," Sullivan said. "Nobody is going to stop us from living our lives the way that we lived our lives before. This is where I live."
Alex's widow, Cassandra Sullivan, joined the boycott. So did Tom Teves, whose own son, Alex, also was killed.
"They can do whatever they want. I think it was pretty callous," Teves said.
Sandy Phillips, a San Antonio, Texas, businesswoman, lost her daughter, 24-year-old Jessica Ghawi, an aspiring sportscaster. She didn't attend, saying she wished Cinemark had asked families about plans for the theater and how they would have liked their relatives to be honored.
"They could have avoided a lot of ill feeling," she said of the company.
Cinemark reportedly spent $1 million on renovations. Before it did, it allowed survivors and families to visit the theater. Jacqueline Keaumey Lader, a U.S. Marine and Iraq war veteran, did so.
"It does help significantly," Lader said. "It's taken the power away from the place."
Associated Press writer Nicholas Riccardi contributed to this report.