One thing hasn't changed with “Shrek”: Puss in Boots still steals the show. The fourth and supposedly final “Shrek” film, “Shrek Forever After,” premiered at the Tribeca Film Festival Wednesday night at New York's Ziegfeld Theatre. It was a glitzy affair for the film, the first in the franchise to be released in 3-D. Given the box-office boost 3-D films have seen - particularly since “Avatar” - the film's studio, Dreamworks, expects a 3-D “Shrek” to be a hit, capping a franchise that has already earned more than $1 billion at the domestic box office. “Shrek Forever After,” which will be released May 21, returns the voice cast of Mike Myers (Shrek), Cameron Diaz (Fiona), Eddie Murphy (Donkey) and Antonio Banderas as Puss in Boots, the Zorro-like feline. The film takes the shape of “It's a Wonderful Life.” A mid-life crisis comes to Shrek, now a father of three, who laments the loss of his younger, wilder days as a fearsome ogre. The evil magician Rumpelstilskin (Walt Dohrn) makes a dubious deal with Shrek, the result being that Shrek was never born and never married Fiona. The bizarro world Shrek encounters - something like the sideways shifts of ABC's “Lost” - is a mishmash of mostly the familiar fairy tale characters, but with different twists of fate. The Gingerbread Man, so meek in previous “Shrek” movies, is now a kickboxing warrior. Puss in Boots, too, has been inverted. In this “Shrek,” the debonair swashbuckler has turned out an obese house cat, too lazy to shoo a mouse drinking from his bowl. He doesn't even have his namesake's footwear.