It’s not an easy task to make a great fantasy movie. First, you must ensure your magical universe offers something unique compared to everything that has come before. Then, you need to explain to viewers your fantasy setting’s rules and internal logic, without which there cannot be relevant stakes.
The few glimpses of magic we get in Slumberland are indeed beautiful to look at. Nevertheless, we can’t help but feel disappointed by the wasted potential of the movie, especially when McCay’s comic strips took us to so many wondrous places. Instead, the film adaptation revisits the same dreams multiple times, a decision that might have cut production costs but also prevented Slumberland from being as breathtaking as it could have been.
Slumberland's second big issue comes from the working of its magical universe. The movie takes its time to set the rules of Slumberland, and there’s no lack of exposition to underline how things work inside dreams. Even so, Slumberland’s script is still plagued with inexplicable coincidences and developments that contradict the principles it lays bare.