First, the staples: There is a family, complete with obnoxious ten-year-old and his brainy sister, a widowed father, and of course, the family dog. As far as the story goes there's an ancient tomb with dinosaur eggs, a stereotypical villain, and very little surprise, which brings us to the dinos themselves...
Although David Allen's stop-motion effects are quite good the plot's use of dinosaurs makes it a rather wasted effort. For the hackneyed reason that they were frozen for seventy-million years the saurians remain the size of house-hold pets. They also behave like cartoon characters in that they mischievously get into trouble and are extremely anthropomorphic. In one scene the tyrannosaurus actually dances to Rock and Roll music, which is--no, it is unbearable. These creatures are NOT dinosaurs.
In trying to emulate the G and PG movies from Walt Disney (which Charlie Band, the director, admits to in the "making of") Moonbeam's effort is blatantly unoriginal, which would be at least okay if the characters in the film were interesting. Yet the biggest problem of all is that Prehysteria is too childish for kids. From an original idea by Pete Von Sholly (see his interviews here on Buried.com)