The beginning of this movie is promising. It sets itself up for self-parody -- satirizing the old cartoon show and its absurdities while also managing to make fun of some clichés of cartoons and feature-film spin-offs.
Then it becomes its own material -- it turns into a disastrously unfunny, stupid kiddie movie with lame fart jokes and surprisingly none-too-subtle, eyebrow-raising sexual innuendo.
Robert De Niro is really wasted here. All he can resort to is mugging up for the camera and making fun of his old movies again -- here we get "You talking' to me?" which was funny the first time he did it. It's become his calling card now -- it's like the first thing he says when he walks on camera is "You talking' to me?" and the director expects everyone to laugh because, hey, it's Robert De Niro, and that's FUNNY.
Rene Russo is wasted too although then again I don't think she was put in the film for her acting skills - they just got her because she looked like the character. Ditto for Jason Whatshisname (from "Seinfeld"), who tries too hard -- I guess he was pretty desperate after the show ended.
Overall this is a disappointment because it begins so promising and turns into a dud.