Marvel Comics did give the crowd a teaser clip of Agents of S.H.I.E.L.D., they gave them the entire pilot!

"There was a whole legal thing with lawyers," screenwriter Joss Whedon mock apologized to the crow for having no clips before saying, "So we can't show you a clip. We're just going to show you the episode."

Ballroom 20 cheered in excitement as the Comic-Con audience was the first to watch the episode, a pilot that many industry reporters and many Hollywood insiders have yet to see, according to Entertainment Weekly.

EW gave their first impressions of the story line:

A couple new S.H.I.E.L.D. team members are recruited as the government organization tries to stop a man (J. August Richards) who was the victim of an experiment that gave him super-powered yet dangerously combustible strength (like the Extremis technology that powered the villains in Iron Man 3). The first episode was very much a weekly procedural drama, with plenty of little character teases to keep you interested.

The dialogue was, to give a shout out to a certain fan site, Whedonesque. It was the best aspect of the pilot, and precisely what you expect from this team. Smart, witty, self referential, with lines playing off your expectations (such as a riff on Spider-Man's "with great power comes great responsibility" line).

Comic Book Resources also gave their overall thoughts about the show:

One noticeable facet of the show was the level of references and in jokes for comic fans and Marvel heads. "Agents of S.H.I.E.L.D." may be the only TV series this pilot season with casual references to cosplay, for example. Being Comic-Con, the jokes and notes in the pilot to both Marvel films and comics played well with the fans.

"Marvel's Agents of S.H.I.E.L.D." will premiere this fall on Sept. 24 on ABC.