- Not so much to do with the film itself but freaky nonetheless. 9 is played by Frodo of the Nine Fingers, who is part of a Fellowship of nine and has the word "nine" tattooed in Tengwar on his hip. Coincidence?
- 7 wears a bird skull. What does she slay? The Beast with a cat-skull head, in the style of 'Usually peaceful herbivore/omnivore defeats the scary predator.'
- The monsters manufactured by the Fabrication Machine get progressively more alien looking as the film goes on. The Cat Beast looks like a giant cat, a very familiar creature. The Winged Beast (according to Word of God) is meant to look something like a dragon, a being that is less familiar and unlikely to be seen in real life. The Seamstress, for all intents and purposes, is a mechanical Eldritch Abomination that looks nothing like any sort of real life entity.
- Save for, perhaps, a monstrous mutant cobra straight out of the Resident Evil series.
- They also invoke the images of monsters from Classical Mythology—the Cat Beast is a giant, implacable feline monster (like the Nemean Lion), the Winged Beast is a predatory avian with a sharp beak and an equally sharp metal projectile (like the Stymphalian Birds) and the Seamstress is a feminine serpent that can immobilize her prey through eye contact (like the Gorgons).
- The general relationship between 7, 3 and 4. The twins appear to be close to 7 with her acting as a maternal figure for them, but the set up of this little group makes sense when you take their numbers into consideration: 3+4=7 after all!
- In the end, you see 1 follow in his own philosophy. In the most tragic of ways. "Sometimes One must be sacrificed for the good of many."
- The Fabrication Machine's core is a spherical object with a single round eye, was the first intelligent creation the Scientist made, is compatible with the talisman that allows him to fragment his soul to give life to new objects, feels a hollow compulsion to absorb more souls into itself, and was designed as a machine that could easily make anything to suit its or other people's needs. It wouldn't be a stretch to say that it was technically "0", a number known almost exclusively for being a foundation to build upon... or the only thing left when everything else has been removed from the equation.
- There are still withered human bodies lying around; presumably the machines' gas not only exterminated life down to the microscopic level but stopped all biochemical processes in their tracks. Pickling gas, perhaps?
- Killing all the microorganisms would make stuff wither a lot slower. In fact, this is how pickling works.
- The bodies are probably mummified. Without living trees and transpiration, inland humidity would've plummeted and rainfall dwindled considerably.
- So, the Fabrication Machine/BRAIN was created and used to make more machines. But why in the world would it have a place to put something that could suck out one's soul? Why would you build a machine with that function—wait. This machine was used during a war. So, any P.O.W.s or anti-war protesters might...Oh God.
- This could've been how the war against the machines got started. The movie claims that the Fabrication Machine turned against humanity because it was corrupted by the military, but it had to get its power from somewhere. Say people figured out what happened to the missing anti-war protesters and, naturally, they had a problem with it.
- It's also worth noting that the Fabrication Machine and the soul-transferring makeup mask were invented by the same guy. The feature-length film even shows on screen him transferring some of his intellect into the machine. There's an implication that they ran on similar technology, but that the "just a scrape" approach the Scientist used with the Fabrication Machine wasn't enough to impart humanity. Without a moral center and compass, the thing was far more inclined to just go berserk - which it did.
- A Wild Mass Guessing for 9 suggests that the dolls' purpose was to be soul-sucked and then have their souls released into the sky so life could be restored to Earth. If that's true, then at least five of those dolls were born just so they could die. And not a nice death, either—a horrible, painful, terrifying one!
- If 7 was able to kill the Cat Beast so easily, why didn't she do it earlier? Did she need it to be distracted?
- I took it that she was probably looking for the others, so killing the Cat Beast wasn't a priority at the moment.