After a buzz-building screening at Harry Knowles' Butt-Numb-A-Thon late last year, the big-screen superhero spoof Kick-Ass will be sticking around in Austin to be the opening night film of this year's SXSW. Based on the comic book series by writer Mark Millar and John Romita, Jr., Kick-Ass follows the often hyper-violent misadventures of a self-made superhero, as well as the youngsters he unfortunately inspires. The film version was helmed by Matthew Vaughn, the one-time Guy Ritchie associate who moved to directing with Layer Cake and Stardust. It opens wide April 16th. Here's the official trailer: