Audience-Coloring Adaptation: Suffice it to say that every post-1956 adaptation of the Exodus story bears the unmistakable fingerprints of The Ten Commandments. Most notably, it's down to this film that the Pharaoh of the Exodus is always identified as Rameses II in popular culture.
Any time Nefretiri says Moses. "Moooses, Moooses..."
A good chunk of the movie swings between this and Narm Charm. It was already kind of old-fashioned for 1956, as more films were being made with naturalistic acting. However, DeMille was a Victorian born and bred, and conceived this picture as a series of theatrical set pieces, called tableaux. You can almost see the curtain fall at the close of each scene. And so the actors spoke that way too.
Signature Scene: Moses parting the Red Sea, along with his delivery of "BEHOLD, HIS MIGHTY HANDS!"
Visual Effects of Awesome: The parting of the Red Sea, accomplished by digging out two parking lots and the section of street between them, to create an artificial waterfall on either side (as miniatures were deemed unconvincing). Years later, it's still the greatest scene ever photographed.
The movie is about godly people seeking freedom from a pagan dictator. In the introduction (theatrical and DVD/Blu-ray releases only), De Mille discusses the central theme of the film as about whether men are free individuals or the property of the state. Remember the era this film was produced in, and consider its possible hidden meanings.
One of the film's themes is that people should be ruled over by set laws rather than the unrestricted whims of a dictator. Thus, the Ten Commandments are framed in quasi-Enlightenment terms as a proto-version of the Magna Carta or the U.S. Bill of Rights. Reinforced by DeMille encouraging the Fraternal Order of Eagles to distribute the now-controversial sculptures of the Ten Commandments tablets to courthouses across the country.
The Woobie: Lilia. Almost becomes a sex slave to Baka, separated from Joshua and forced to give in to Dathan to save Joshua, and nearly becomes a human sacrifice. The lyrics to her Leitmotif are "Death cometh to me to set me free".