DC Comics last night debuted the 30-second trailer that will air on television and in theaters to promote the September relaunch of its superhero line. Hero Complex also has a two-minute cut that will appear, presumably later today, on the publisher's website and Facebook page.

The trailer smartly focuses on DC's marquee characters, the superheroes a general audience will recognize -- Superman, Batman, Wonder Woman, Green Lantern, The Flash, Aquaman and the combined Justice League. That said, it's difficult to get past the promo's shortcomings, which aren't limited to the generic "metal" soundtrack, or the feeling that the teaser tumbled out of 2009, when countless independent creators and small publishers were using the same techniques to animate and market their own comics to existing readers.

No, the major problem is that there's no substance, and no excitement, to the trailer, nothing to make the "average" film-goer sit up and think, "When I get home in three hours, I just have to check out that website!" (Now what was that website again?) "All-new" doesn't tell a non-comics reader anything; neither do Star Trek-style lens flares and tilted, static shots of characters a mainstream audience has seen fully realized on film and television.

There's the sense that DC desperately wants to target a new audience, but doesn't quite know how. What the publisher does instead is fall back on the approach it uses for the readers it already has. For additional evidence, look no further than the extended version of the trailer: The only differences between that and the one airing in theaters is that it's longer, and includes the tagline, "The World's Greatest Super Heroes ... The World's Greatest Creators."

"DC Comics: The New 52" kicks off Aug. 31 with the release of Justice League #1.