Dark Souls' developer From Software has no plans to release a demo for the game prior to its release.
Speaking to Japanese site 4gamer, kindly translated by Andriasang, director Hidetaka Miyazaki explained that it would be impossible to convey the appeal of the game in a brief demo. And in any case, he explained that he's "not all that great at making demos."
He also put the dampers on DLC talk, insisting there were no plans at present to add to the game post-launch. He didn't completely rule it out, but if it did happen it wouldn't involve charging for additional items. These will be rewards for discovery and work, Miyazaki said, rather than for those with deep pockets.
He added that if From Software felt it could do something interesting online using the Dark Souls engine, additional downloadable content might appear at some point.
The spiritual follow-up to From Software's widely acclaimed 2009 RPG Demon's Souls is due for release on PlayStation 3 and Xbox 360 at the end of the year.