During the private banquet with Esther, Xerxes, and Haman, a close-up on Esther shows no necklace around her neck, yet in the next cut, where we see her from the side with Haman, the necklace is back.
When Esther is running to see the king to plead for the Jews the scene switches back and forth between Xerxes, indoors, and Esther, outdoors. Esther is running through pouring rain yet when Xerxes is shown sunlight can be seen shinning through the windows onto the floor and across the faces of those in the room.
When Esther is in the courtyard of the harem eating she throws food to a monkey. When the camera shows Esther tossing the food it is obviously a thin sliver of meat, however when it cuts to the monkey picking up food it is a banana, or some soft white/yellow fruit. These shots are shown twice.
When Esther is seen watching the caravan arrive at the beginning, she is wearing a white dress with a wrap. When she goes inside to talk with her uncle, she is wearing a bright, multi-colored dress and headband.
In one scene when the King is drinking from a goblet, there is an orange price tag on the bottom of the glass.
The entire use of the Star of David. The Star of David was not used as a symbol of Judaism until the Ottoman era of the Middle Ages. Esther lived during the 5th century BC.
Esther has "tan lines from bathing suit" in wedding feast scene
When King Xerxes is mounting his horse on the training grounds the saddle is very clearly a modern leather "western" style saddle complete with a horn (for roping cattle).
In one scene, you can see the "mark" a character is supposed to hit, taped to the floor.
The part of Hegai, the Royal Eunuch is played by Tommy 'Tiny' Lister, who has a deep, resonant, basso-profundo voice. Hegai says the same sword that cut his eye in battle took his "manhood." A man castrated as an adult is technically a 'eunuch' and could have such a deep voice. However, eunuchs were more often castrated on purpose before puberty resulting in a higher pitch.