The reason the cannibals' hands shake is that they suffer from Kuru disease - a form of Creutzfeld-Jakob Disease caused by eating human brains or spinal columns. The first symptom is shaking limbs, which is why people check Eli's hands throughout the movie.
When Eli first sits in the room Carnagie imprisons him in, a poster of the movie A Boy and His Dog (1975) is visible. A Boy and His Dog (1975) is recognized as one of the earliest post-apocalyptic movies, and a source of inspiration for many dystopian and post-apoctalyptic movies and video games.
The film didn't explicitly mention that the apocalypse was because of a nuclear war; writer Gary Whitta preferred to leave clues of the apocalypse instead. There are a few clues that indicate nuclear war, like the large bomb craters the characters are sometimes near.
When Eli encounters a group of road bandits, behind them is a tunnel structure with a bold 14:6 written on top. Being a post-apocalyptic movie, that writing can be referenced to an apocalyptic book in the Bible, Revelation. Revelation 14:6 (King James Version): "And I saw another angel fly in the midst of heaven, having the everlasting gospel to preach unto them that dwell on the earth, and to every nation, and kindred, and tongue, and people."
Promotional material for this film was used by fans as a rumored movie for the video game series 'Fallout'. This film holds many similarities with the popular game franchise, but is not said to have been an inspiration.
The names of the characters, George and Martha, are a direct reference to the play 'Who's Afraid of Virginia Woolf?' by Edward Albee. The play is about an elderly couple who want children so badly, they invent a dead son; their names here are an ironic reference to the "Father and Mother" of the United States, George and Martha Washington.
The cooling towers, in which Eli and Solara take refuge, are most likely the cooling towers of the former Rancho Seco Nuclear generating station outside of Sacramento, California, given the apparent travel time on foot and by vehicle before Eli and Solara reach the Golden Gate Bridge, and Carnegie returns to his town.
While the antagonist of the film has the last name Carnegie, who sought out books, Andrew Carnegie was an industrialist/philanthropist in the early 20th century who donated money to communities to build libraries.
Eli carries a King James Bible that he reads every day, and when he quotes Psalm 23, he quotes it as a New King James Version. Also shown at the end when they are done with transcribing and printing to book.
The film has many parallels to the Fallout video games, in particular Fallout 3. In both the book and the film, there is a very similar-looking apocalyptic wasteland, gangs of thugs with ambush tactics, self-contained communities, cannibal families and American landmarks being used as places of salvation. Actor Malcolm McDowell appears in both the film and the game, although their characters are not similar.
'Childhood Memories' (composer- Gheorghe Zamfir pan flute artist) was being "whistled" by the villain in the van abducting Solara after they left the church yard scene. The piece was originally composed for Sergio Leone's final film, Once Upon a Time in America (1984).
The tenth film released in select D-BOX enabled cinemas, located in the U.S and Canada. In D-BOX's words, the motion control technology "adds to the movie's plot and underlying themes of fear, terror and explosive action by offering realistic sensations during most of the film's action scenes."
The trivia items below may give away important plot points.
The King James Bible is roughly 789,000 words long. To write it out longhand, at twenty to thirty words per minute, it would take roughly 31,000 minutes. Assuming the writing was done for 8 hours a day, this would take 66 days to complete.
Hints to Eli's condition are shown throughout the movie: In the opening fight, he cuts the man's hand off after being pushed, waiting until he's touched to get a sense of where to direct his blow with his machete. Also he lures the rest of them in to a dark tunnel before fighting them.-In the house at the beginning, Eli looks at the sun from a window, but his eyes don't dialate. He has extraordinary hearing and sense of smell. At one point, after staying the night at the cooling tower ruins, Solara asks Eli how does he know which way to go, to which he replies "We walk by faith, not by sight". He doesn't put on his sunglasses right away when walking outside, like everyone else does (he even appears to be staring directly at the sun). In several scenes sounds of babies, shooting guns, movement and sometimes almost insignificant sounds are emphasized. He searches the shelves of the first house he checks (in the beginning of the movie, before he finds the dead body) by running his hand over them. When he finds the dead body hanging it is very clear that his shock is caused by the doors falling off the hinges, not the sight of the dead person. He even feels the body before being sure of what he is dealing with since he can't see anything. Just before finding the doors hiding the dead body, he runs into an end table with his thigh, as if he didn't see it. As he walks along the highway with Solara, he silences her so that he can hear the bird ("dinner") flying above them. At George and Martha's house, he kicks forward by the first step of the stairs to the porch with his boot so he knows where it is. He never fires his weapon first, needing to hear the sound of shooting at him to identify the location of his target. His use of a shotgun as a primary weapon means that accuracy is not as critical, allowing for him to aim via sound rather than sight. When Eli and Solara approach the cannibals' (George and Martha) house. As they approach the steps, you can hear a brief clicking sound. Eli is using echolocation to "see" what is ahead of him.George asks Eli about the No Trespassing sign, "Can't you read the sign?" Eli responds, "Didn't see it." -When paying for his trickle charge, he opens a Zippo lighter and passes his hand over the flame to ensure it indeed was lit instead of seeing the flame.
Throughout the film, it is said that Eli's Bible is the only one remaining. After the newly printed Bible is put on the shelf, beside it, there is a book with a Hebrew headline saying "Tanach." Tanach is the Hebrew Bible, the Old Testament of the King James version, meaning part of a Bible was already found, but it's likely no one knew how to read it.
Aside from the film's title, Eli is identified by name only three times. Once, when it appears on a K-Mart name tag inside his backpack, again when Eli introduces himself at Alcatraz Island, lastly on the "head stone" in the end sequence.
Keeping with the film's ideas of religious faith and belief, there is symbolism in the scene where Redridge executes the guard who didn't stop Eli's escape; the guard is shot in the head in front of the corner of two walls, and when the blood spray goes across the walls and down the border of them, it forms the shape of a cross.
British-born actors Gary Oldman and Malcolm McDowell have both starred in sci-fi films with settings in an alternate, historical version of San Francisco, Ca. "Dawn of the Planet of the Apes" (2014) and "Time After Time" (1979), respectively. Each film had a grim premise for the city's population.