The concept of playing a character has long seemed alien to Martin Lawrence, who has coasted on his screaming, bug-eyed shtick for way too long. So, it's a pleasure to see him actually stretch a little bit--even playing the straight man in a buddy comedy--as he inhabits the voice of a giant domesticated grizzly named Boog, who is prematurely released into the woods after a hyperactive deer (Ashton Kutcher) gets him into trouble.
When the two of them are simply riffing in free-form environments, the movie has its own unique energy, but before long, they get forced into a plot, and kiddie-animation clichés start rearing their ugly heads, left and right--along with some completely inappropriate innuendos and a scene shot like a horror movie that may be too much for the little ones.
The animals versus hunters angle the film ads are hyping doesn't actually take place until the very end of the movie, and most of the supporting characters you see on the posters are extremely peripheral--some subplots are suggested, then dropped entirely. If you get a chance to see the film in 3-D IMAX, though, the letter grade goes up a few notches, as the experience of having a giant screen full of Froot Loops flying right at you is the birthright of every American.