The big "what if?" powering Pixar's The Good Dinosaur is introduced in the first few minutes as a throwaway gag: An asteroid veers out of orbit and careens toward a young, green planet, ignites into a cataclysmic fireball as it passes into our atmosphere, then streaks across the night sky as a shooting star on a collision course with Earth...and misses. The startled dinosaurs immediately return to chewing cud, and (prehistoric) life goes on.
In this alternate history, millions of years of undisturbed evolution have allowed herbivorous dinosaurs to develop an agrarian society (along with an ability to speak English). On one small homestead, dino parents Poppa (Jeffrey Wright) and Momma (Frances McDormand) welcome the hatching of their three children: fearless bully Buck (Marcus Scribner), cheerful Libby (Maleah Nipay Padilla), and anxious Arlo (voiced as an older child by Raymond Ochoa). Buck and Libby quickly adjust to the demands of farm life, but Arlo's knees quake whenever he has to feed the prehistoric chicken-beasts. Poppa wants him to grow some backbone, and not just because it'll make his chores easier: Dinosaur culture values "making a mark" -- putting a muddy footprint on the corn silo in the center of the farm -- as a symbol of one's esteem, and you can only make one after you've earned it by performing a monumental feat. Poppa tries to push his son toward manhood (dinosaurhood?) by giving him the task of nailing the "critter" that keeps plundering the silo, but when Arlo discovers that the critter is actually a feral Neanderthal child (Jack Bright), his hesitation to hurt the creature sets off a series of events that will force him to face his fears -- irrational and not -- with sudden urgency.
Pixar's depictions of this alternate Earth's unspoiled natural world are extraordinary, with magnificent, sun-capped mountain ranges and rivers that roil and seethe just like the real thing. And the supporting characters that are allowed to show some sardonic grit, like the trio of pterodactyls whose lower eyelids twitch as they explain the theology of their tornado-centric cult with a little too much zeal, strike just the right balance between wry and silly for an intelligent children's movie. But, regrettably, most of the dinosaurs are not particularly charismatic, least of all Arlo, with his knobby knees and complexion of a Chinese winter melon. He blunders into peril so often, and with such quavering cowardice, that he wears out his welcome pretty quickly. (Birds might have evolved from dinosaurs, but science still hasn't proven that any of them were ever this chickenhearted.)
Indeed, the whole movie is an atavistic throwback to the kind of plodding, punitive morality tale that owes less to the whimsy of Toy Story and more to the vengeful tradition of cautionary Struwwelpeter fables. It's bad enough that the film's moral theme of "you have to overcome your fears" is made abundantly, explicitly clear early on, but even worse, terrible deus ex machina events rain down from the sky every time Arlo fails to muster up enough courage. The movie demonstrates over and over again that fate will punish you if you fail to face your irrational fears, usually via scenes of peril and grief that will tax the emotional resolve of younger or more sensitive children. After the subtlety and complexity of Inside Out, The Good Dinosaur is a disappointing evolutionary regression to the bad old days of "fun for the whole family" films that were neither fun nor for the whole family.