Millennium Partners has yet another vision for the skyscraper it wants to build in downtown Boston.

The developer has shared new images with a city design review panel, showing off a 690-foot building that almost looks like two distinct towers in the heart of the Financial District. There are also new images of the “Great Hall,’’ a public lobby that would run between Devonshire and Federal streets.

Approval of the $1.3 billion project by the Boston Planning & Development Agency was originally scheduled for this week but was delayed at least a month while Millennium and the agency continue to work on the design of the skyscraper, which will hold offices and condominiums.

Members of a city architectural review board said the building Millennium proposed earlier this year was too massive for the site and “uninteresting’’ for such a prominent place on Boston’s skyline.

Millennium says it aims to start construction later this year on the site of a now-demolished city garage, which it is buying from the city for at least $153 million.

Tim Logan can be reached at tim.logan@globe.com. Follow him on Twitter at @bytimlogan.