From the very beginning everyone behindhas been frank about hoping for a sequel-- though in the cautious, "we'll have to wait and see how it does" way that pretty much everyone is before their movie opens (being the rare recent exception ). In early 2012 word broke that director Marc Forster was imagining the film as the beginning of a trilogy, but that was before the movie's ending was completely changed , leading to an avalanche of bad press and the sense that Paramount was just aiming to get the film out there, try not to totally lose their shirts on it, and forget all about it.And then the power of Brad Pitt showed up to surprise us all.made an estimated $111.8 million worldwide this weekend, a remarkably strong debut for a non-sequel, decidedly non-family movie not based on a familiar property (Max Brooks's novel is great, but not exactly household name). Confident all over again, Paramount has told THR that they will now be actively developing a sequel, though the original plans for a trilogy seem to have at least been sharply altered back when the ending was changed. The current ending of the movie certainly leaves plenty of room for a potential sequel, and given how littleused from Brooks's novel, they could mine entire scenes and story lines from there alone.You might think that Pitt would be less than eager to return to a film that required him to do unbelievable amounts of publicity , but as a producer of the film he was a champion for it the entire time, and it's a huge hit for his Plan B Entertainment in addition to Paramount. It's also, unbelievably, the biggest opening of Pitt's career. Sure he's earned critical acclaim and significant box office success with recent prestige picks likeand, but the ability to make sure a blockbuster opens big is a major element of being an A-list star, and it's something Pitt has done far less often than Tom Cruise, Will Smith, or even Angelina Jolie. Pitt and Jolie's shared best-ever opening was, until Jolie bested it within 2008.will doubtlessly be one of the summer's most unlikely success stories, and Paramount has to feel confident going into a sequel because, hey, now they know they've at least come up with one version of the story that can work. If you sawthis weekend-- and based on the box office numbers, a lot of you did-- let us know if the movie had you interested in a sequel. If you've got ideas for that sequel too, by all means, share them in the comments.