'Avengers' scores No. 2 opening day with $80.5M

San Diego Comic-Con kicks off today and Marvel is celebrating with new concept art for "The Avengers" sequel out next summer and it doesn't look good for our heroes. Marvel debuted four posters of Captain America, Iron Man, the Black Widow, and new character the Scarlet Witch attempting to fight off hordes of robots. 

Entertainment Weekly's latest issue has a huge 11-page spread on the "Avengers" sequel revealing what to expect from possibly the biggest movie of 2015.

When you have a movie that's so universally beloved as "The Avengers," how do you follow that up? Joss Whedon's answer: You make a movie that's funnier, more human, and more challenging — not just for the characters on screen, but for the audience as well.

There are minor spoilers below. "Avengers: Age of Ultron" is almost as good as "The Avengers," but not quite.

Disney/Marvel

When you think of the Avengers, you most likely think of Iron Man, Captain America, Thor, the Hulk, Black Widow, and Hawkeye.  After all, that's how the group has been depicted on screen in the Marvel Cinematic Universe. However, if you've been a longtime fan of the group, you know the it has consisted of over 80 rotating members since the inaugural Avengers issue in 1963.

In order to understand Marvel's approach in promoting the highly anticipated The Avengers movie, it's necessary to step back in time to 2008. Five years ago, Marvel executives developed a comprehensive plan involving four superheroes to culminate with one "uber" movie, says Marvel's Paul Gitter. "We took the superheroes ??? Iron Man, Captain America, Thor, ...