"We're Back!" combines elements of "Jurassic Park" and "Back to the Future" for a disappointing animated feature from the Steven Spielberg factory — especially when you consider what Spielberg has done for children's cartoons on television.

Spielberg's "Tiny Toon Adventures" and "Animaniacs" are fast and funny, witty and smart — everything "We're Back!" is not.

The film begins with an anachronism as a baby bird attempts to take flight too early and drops on the snout of a huge, goofy-looking Tyrannosaurus rex. Rex (John Goodman) is sporting a sweater as he plays golf outside of modern-day New York City.

To encourage the bird not to grow up too soon, Rex tells his story, which we see in flashback.

Millions of years ago, Rex was just another rampaging monster. But he got a second chance when kindly Dr. NewEyes (Walter Cronkite) arrived in his time-traveling space ship and fed Rex Brain Grain cereal, which gave him intelligence and a gentle personality.

Aboard the ship, Rex met Elsa, a pterodactyl (Felicity Kendal); Dweeb, a duck-billed hadrosaurus (Charles Fleischer); and Woog, a triceratops (Rene LeVant), who would become his traveling companions.

NewEyes sends them to 1993 New York, to fulfill children's wishes of seeing real, live dinosaurs at the Museum of Natural History. But, of course, the foursome is sidetracked.

They take up with a couple of neglected children and land in the clutches of evil Dr. ScrewEyes (Kenneth Mars), who operates the Eccentric Circus in Central Park and who plots to use the dinosaurs as sideshow exhibits.

There is some wonderful animation here and a couple of chase scenes get the blood pumping (with terrific computer-generated backgrounds). But aside from one character who appears toward the end — an off-the-wall clown (Martin Short) — there is not enough imagination or humor.

The screenplay, by John Patrick Shanley, who won an Oscar for his "Moonstruck" script, panders to the kiddie audience and is weak and plodding.

There is another, much better dinosaur cartoon with Stephen Spielberg's name on it, of course.

No, not "Jurassic Park." Don Bluth's "The Land Before Time," which was also produced by Spielberg.