It takes a keen eye to spot them, but some of the holes are the size of children. Imagine how the parents must feel when their child disappears...and comes home looking like that. Assuming they can even walk or talk when they emerge, the psychological trauma alone will have reduced them to gibbering lunatics.
Or, what if the parents, in their own mad desire to enter their holes, bring the kids with them...
Some of the holes have it where the person has to bend their neck a little. Consider how they stretch enough that those whose hole was that of normal stance do get their necks bent at some point.
Only some holes seem to go all the way through. Assuming the holes keep people magically alive during their hole stay, then anybody with a blocked hole (such as Nakagaki, unless he was just as the point when his body would have to stretch) would end up spending eternitynote or until somebody dug them out stuck in one spot and alive. And, judging from the researcher near the end who comments on the fault on the other side of the mountain being much smaller than the entrance fault, this likely happened to most of the people who went in.
It's possible that, given the shapes of the exit holes, the other fault is still large enough to accommodate everybody. Let's hope this is the case, anyway.
Where is it stated that there needs a one-to-one correspondence between entrance holes and exits holes for everyone to get out? Maybe some of the tunnels run into each other...
Or maybe some split...
It may just be the effect of shadows, but the spaghetti-men who emerge at the end appear much darker than those who entered... most likely as a result of having all their innards squashed until they burst.
In the dream, the holes serve as a means of punishment for "a horrible crime". It's possible that the holes exist because everyone at the site is guilty of doing something terrible.
Or, perhaps, the past-people are dicks, and just want to get their spiteful revenge on all the future people who have survived the collapse of their civilization.
Yet, how would they even know what future people would look like? Unless they can see into the future, or something was telling them to.
The holes are angled slightly downward so people go in. As part of the silhouette, there's a big pointy piece of rock pointing at the crotch. It's like if someone turned a wooden horse into a slide.
What's so creepy about that?
You...don't find anything additionally unnerving about all the rest of the stuff happening while sliding down a big pointy wedge jammed up into your genitals?
Everyone would have died of starvation long before they reached the start of the stretching part, much less the end of the hole... unless A Wizard Did It, which would also explain how could somebody carve the holes to start.
A Wizard Did It would also explain how they could stretch so thin in the first place. Bones don't squish or stretch. However, this may be why Nakagaki got stuck: he was one of the unlucky (or is that lucky?) ones for whom the magic didn't work.
It might be worse for him: what if you have to force every single step once you start to get stretched?
It doesn't seem like there's anything preventing people from just moving their arms forward, since most people's arms get narrower as they get further from the shoulder. Even if the holes really are carved that perfectly to people's body sizes, the body is flexible enough that you should be able to pull out your arms. After that, you might be able to get out your legs, and from there, all it would really take is turning yourself around. Of course, most people were likely too rapt by the holes to consider doing this, but someone like Nakagaki probably doesn't want to be there anymore. Getting your head out would be difficult, but maybe it wouldn't be as bad if you could at least move your arms around a little...
The narration during the second dream did state that the holes were somehow made that it was impossible to go back to the entrance. How this worked, exactly, wasn't explained, but presumably it kept the people in the holes from walking backwards or turning around to get out.
Yet the miner who went in to try and get Nakagaki out was able to go inside and come out when he wasn't able to find him.
I realize this isn't what horror is about, but exactly what good does it do anyone or anything for noodle people to exist?
The geological structure presented is a fault. It's a location where the rock has separated along a plane, one side pushing up to give a smooth surface. The fault occurred recently. So logically, there would be a rock facing underground that would have lined up perfectly with the exposed face before it split. If the holes aren't man made, it stands to reason they continue underground along the original whole volume into who knows what shape. Perhaps a shape men once held.