One of the coolest things about Comic-Con is the very early screenings of movies that studios trot out to garner buzz and get mouths talking at the event. In recent years, Tropic Thunder, Inglorious Basterds and District 9, among others, have all been Comic-Con fodder, as Scott Pilgrim vs. The World has been this time around. The horror movie The Last Exorcism (in theaters Aug. 27) screened tonight for folks, and it’s a rather impressive recent film in the genre. Told in faux documentary style, the story follows Louisiana holy man Cotton Marcus (Patrick Fabian), the youngest in a long line of exorcists. But unlike his predecessors, he doesn’t believe in demons and thinks “exorcising” them from people is a load of hooey. Cotton decides to take a camera crew along to film how much hooey it exactly is when a teenage girl named Nell (Ashley Bell) is thought to be possessed, and the preacher doesn’t quite know what to believe anymore when he finds something seemingly otherworldly: Is a supernatural force afoot, or is it just this girl’s insanity talking? It’s creepy (much more than that last “buzzworthy” horror film, Paranormal Activity), really well made and as funny as a movie can get about exorcising demons. And in a time when most movie special effects are all done on computer, only one digital effect exists in The Last Exorcism, which was revealed during a Q&A session with the filmmakers, including director Daniel Stamm and producer (and horror nut) Eli Roth. Roth shared a story that as a kid he always thought he was going to be possessed by the devil, “until my mother told me Jews didn’t believe in the devil,” and he was asked by one person if he was concerned about the movie being compared to the 1968 classic Rosemary’s Baby. “Better that than Repossessed,” Roth reasons. “We hope it’s a Rosemary’s Baby for a new generation.” Read below for more highlights from yesterday’s Comic-Con schedule.

Photos courtesy of Lionsgate, Paramount Pictures/Marvel

Superheroes were the main attraction in Hall H, which was also the site of a violent stabbing incident. During the Warner Bros. panel in the morning, Ryan Reynolds (looking rather buff) showed off some early footage from Green Lantern — we’ll have some video of him talking about the movie up on the blog soon! — while some fans were more visually impressed with director Zack Snyder’s 1950s female revenge fantasy Sucker Punch. And not to be outdone by a guy with a green power ring, Marvel Studios packed their own punch. Three of them to be exact: Chris Evans and Hugo Weaving were on hand to show some brand new footage from Captain America: The First Avenger; Thor stars Chris Hemsworth (pictured at left) and Natalie Portman brought along a 3D trailer; and director Joss Whedon brought out his whole superhero team for The Avengers, including Hemsworth, Evans, Robert Downey Jr., Scarlett Johansson and Samuel L. Jackson, as well as the recently signed Jeremy Renner and Mark Ruffalo who are playing Hawkeye and the Hulk, respectively.

Harrison Ford wowed the Comic-Con crowd by making his debut at the event during a panel for Jon Favreau’s Cowboys vs. Aliens, a sci-fi Western flick co-starring Olivia Wilde and Daniel Craig that will have some serious buzz coming out of Comic-Con. Earlier in the same Universal Studios presentation, Simon Pegg, Nick Frost and Seth Rogen got the home crowd going with scenes from Paul, a comedy that’s actually set at Comic-Con.

And over in the TV world: Linda Hamilton is guest-starring on NBC’s Chuck as the mother of the title super-spy (Zachary Levi); audiences will finally get to see what the alien Visitors look like on the ABC series V; and The Simpsons announced some intriguing guest voices for the 22^nd season, including Jon Hamm, Hugh Laurie, Cheech & Chong and the cast of Glee.

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