“Slumberland,” the latest big-budget adventure film from Netflix, is something like an “Inception” for kids, featuring a precocious young girl, a cute stuffed pig, and a towering, stinky sidekick. Written by David Guion and Michael Handelman, “Slumberland” has some snazzy fun with the concept of how dreams take us to similar experiences—about forgetting to wear pants, driving a runaway truck, or endless staircases.
