UPDATED 3/28/16 2:20 PM PT: Warner Bros. Home Entertainment has confirmed to CBR News that July 16 is not the correct release date for the "Batman v Superman: Dawn of Justice" Ultimate Cut, contrary to what has been widely reported, and that a date is still yet to be announced. The following article has been amended to remove the inaccurate information.
Original story: "Batman v Superman: Dawn of Justice" director Zack Snyder explained the origin of the upcoming "Ultimate Cut" home release during an interview with Collider, saying, "We call it the 'Ultimate Cut' because to me it's a deeper dive into that world and there are storylines in there that get fleshed out by the longer version… I would say that we didn't really take out much of the Superman/Batman story because I felt like, you know that's kind of the movie, but there was some sort of interstitial stuff that surrounds the story, that kind of finishes some of the ideas that we trimmed back, and I think that's what you get."
As to why the film will be R-rated, he said, "There's a little bit of action, there's a little bit of violence that we trimmed out for the MPAA that we put back. The Batman warehouse rescue, there's a couple shots of Doomsday that were too intense. Then there's a little bit longer ending, sort of the ending sequence, and the opening of the movie, the North Africa sequence is really much different."
He also discussed why the film was cut down to two-and-a-half hours, despite there being almost thirty minutes of extra footage. "It was really just a function of time, to be honest," he shared. "Because the movie's long now, long-ish -- I don’t think it's long, but when you get over two and a half hours the studio starts getting nervous. I'm not James Cameron, who's like 'No, it's three hours, suck it!,' which is cool by the way. I just wanted to try and get it to a length that is work-able."