"The average play thru for part 1 is 2:15-3 hours," Levine said. "We've seen more for people who dig (one guy went five!) and we've seen less for people who aren't interested in the story."
Burial at Sea lead level designer Andres Gonzalez added that the upcoming expansion is "more open" than the main BioShock Infinite experience.
"So there is a lot of optional content to explore and see," he said.
Also during the AMA session, Levine revealed that Burial at Sea - Episode One will be sent to Microsoft and Sony for certification by the end of the week. The content is expected to be officially released on Xbox 360 and PlayStation 3 before the holidays, but no exact date has been announced.
"Submission can take some time, and if the first-parties bounce it back, we'll have to resubmit. We want to super sure before we have a date, but it will be before the holidays and hopefully fairly soon," Levine said.
Concerning Burial at Sea - Episode Two, Levine said Irrational Games is "working our asses off on it," but there is no estimation yet on when the content will be released.
Both expansions are set in the original game's Rapture and are described as narrative-driven and meant to tie the story of Elizabeth and Booker together.
Gameplay has been modified to give players an "original BioShock combat experience" that aims to meld the best parts of BioShock and BioShock Infinite. New weapons, Plasmids/Vigors, Tears, Sky-Lines, and Big Daddies will be featured.
Burial at Sea - Episode Two will have gamers playing as Elizabeth "as she seeks to bring closure to her story" and the overall BioShock Infinite narrative. No other information about this expansion has been announced.
Episode One and Episode Two will sell for $15 each when they launch and are included with the $20 BioShock Infinite DLC season pass.