The lost civilization of Atlantis returns in “Age of Mythology: The Titans,” Ensemble Studios’ expansion to the hugely popular title, “Age of Mythology.” The expansion pack includes a new single-player campaign, scores of new mythological units, the ability to promote units to heroes, and, of course, the opportunity to harness the awesome powers of the Titans. The battle for heaven and earth continues as the Atlanteans enter the “Age of Mythology.