The full cast of Avengers: Age of Ultron (minus Scarlett Johansson) were present at Marvel's Comic-Con panel on 26 July where they unveiled some really exciting though reportedly dark footage from the upcoming superhero film.

Robert Downey Jr, Chris Evans, Chris Hemsworth, Mark Ruffalo and Jeremy Renner were on hand with other cast members from Avengers: Age of Ultron, including Samuel L. Jackson and Colbie Smolders.

Unfortunately the footage did not make it to the web but here's a description of that first clip (via MTV):

We open on Avengers Tower, a post-mission party. The game is to pick up Thor's hammer. Tony goes first and adds an Iron Man hand to help. Rhodey can't even help. Cap tries and nearly moves it, making Thor look nervous.

Ultron, looking only partially complete, stumbles onto the scene. He's clearly made from Iron Man parts. He talks about the problem with the Avengers and why they are unworthy, before sending in drone suits to attack them.

"This is the end," says Tony. "The end of a path I started us on."

We then see a fight between Hulk and Tony in his Hulkbuster armor. It looks like a hell of a battle.

The footage ends with Cap's shield broken. Tony wakes up to see the Avengers scattered on a rock that looks like it's floating in space.

"The feeling of the footage is truly global. We were transported around the globe. There's so much to see, all passing by quickly. Loki's staff makes a cameo, along with Andy Serkis in human form," states the MTV report.

You can watch the Avengers: Age of Ultron panel at the 2013 San Diego Comic-Con below: