Adaptation Displacement: Oh, everyone knows it's an extremely loose adaptation of the book of Exodus, but did you know that this movie is also an extremely loose adaptation of three different novels, the writings of Philo and Josephus (which Demille acknowledges in his opening remarks), and The Qur'an, and a remake of Cecil B Demille's own 1923 movie The Ten Commandments?
"Blind Idiot" Translation: Not quite as harsh, but "Sephora" for Tzipporah and "Yochabel" for Yocheved are very odd translations.
Narm: Any time Nefretiri says Moses. "Moooses, Moooses..."
A good chunk of the movie swings between this and Narm Charm, at least by today's standards. Back when the film was made, this kind of acting was probably the norm.
Actually 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 creating an artificial waterfall on either side. Over fifty 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".