Steven Spielberg has spent nearly 50 years asking whether humanity is alone.

Disclosure Day, a new extraterrestrial tale from Steven Spielberg starring Emily Blunt, Josh O’Connor, Colin Firth and Colman Domingo, is winning over Rotten Tomatoes critics in a big way.

Much of the film is thrilling and mysterious (disturbingly so at times), as Spielberg whizzes the audience through beautifully executed sequences, including a death-defying train action scene, which i...